In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen contents, or cause an application crash, because of incorrect permissions.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:20575 advisory.

    Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop     environment not only on the machine where it is running, but from anywhere on the Internet and from a wide     variety of machine architectures. TigerVNC is a suite of VNC servers and clients.

    Security Fix(es):

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in     XKB geometry processing. (CVE-2026-34000)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information disclosure or Denial of Service via out-of-bounds read in     XKB modifier map handling (CVE-2026-34002)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:20576 advisory.

    Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop     environment not only on the machine where it is running, but from anywhere on the Internet and from a wide     variety of machine architectures. TigerVNC is a suite of VNC servers and clients.

    Security Fix(es):

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in     XKB geometry processing. (CVE-2026-34000)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information disclosure or Denial of Service via out-of-bounds read in     XKB modifier map handling (CVE-2026-34002)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0377 advisory.

    Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

    CVE-2026-33999:
    A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB     compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer     read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other     severe impacts.

    CVE-2026-34001:
    A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence     triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the     X11 server can exploit this without user interaction, leading to a server crash and potentially enabling     memory corruption. This could result in a denial of service or further compromise of the system.

    CVE-2026-34003:
    A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a     specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This     could result in the disclosure of sensitive information or cause the server to crash, leading to a Denial     of Service (DoS). In certain configurations, higher impact outcomes may be possible.

    CVE-2026-34352:
    In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen     contents, or cause an application crash, because of incorrect permissions.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:19342 advisory.

    Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop     environment not only on the machine where it is running, but from anywhere on the Internet and from a wide     variety of machine architectures. TigerVNC is a suite of VNC servers and clients.

    Security Fix(es):

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in     XKB geometry processing. (CVE-2026-34000)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2026:0108 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2026-33999:
    A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB     compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer     read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other     severe impacts.

    CVE-2026-34001:
    A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence     triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the     X11 server can exploit this without user interaction, leading to a server crash and potentially enabling     memory corruption. This could result in a denial of service or further compromise of the system.

    CVE-2026-34003:
    A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a     specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This     could result in the disclosure of sensitive information or cause the server to crash, leading to a Denial     of Service (DoS). In certain configurations, higher impact outcomes may be possible.

    CVE-2026-34352:
    In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen     contents, or cause an application crash, because of incorrect permissions.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2026-592:02 advisory.

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)
      * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential     memory corruption (CVE-2026-34001)
      * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)
      * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:13414 advisory.

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-13414 advisory.

    - Fix CVE-2026-33999, CVE-2026-34000, CVE-2026-34001, CVE-2026-34002,       CVE-2026-34003 xorg-x11-server: various XKB and XSYNC vulnerabilities       Resolves: RHEL-163203       Resolves: RHEL-163271       Resolves: RHEL-163257

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:13414 advisory.

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)
      * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential     memory corruption (CVE-2026-34001)
      * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)
      * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:13414 advisory.

    Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop     environment not only on the machine where it is running, but from anywhere on the Internet and from a wide     variety of machine architectures. TigerVNC is a suite of VNC servers and clients.

    Security Fix(es):

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2026-530:01 advisory.

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)
      * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential     memory corruption (CVE-2026-34001)
      * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)
      * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:10739 advisory.

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)
      * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential     memory corruption (CVE-2026-34001)
      * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)
      * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:10739 advisory.

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-10739 advisory.

    - Fix CVE-2026-33999, CVE-2026-34000, CVE-2026-34001, CVE-2026-34002,       CVE-2026-34003 xorg-x11-server: various XKB and XSYNC vulnerabilities       Resolves: RHEL-163212       Resolves: RHEL-163280       Resolves: RHEL-163266

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:10739 advisory.

    Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop     environment not only on the machine where it is running, but from anywhere on the Internet and from a wide     variety of machine architectures. TigerVNC is a suite of VNC servers and clients.

    Security Fix(es):

    * xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map     handling (CVE-2026-33999)

    * xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory     corruption (CVE-2026-34001)

    * xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory     access (CVE-2026-34003)

    * TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of     service via incorrect permissions (CVE-2026-34352)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:1360-1 advisory.

    - CVE-2026-34352: Fixed permissions to prevent other users from observing the screen, or modifying what is     sent to the client. (bsc#1260871)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:1303-1 advisory.

    - CVE-2026-34352: Fixed permissions to prevent other users from observing the screen, or modifying what is     sent to the client. (bsc#1260871)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES12 host has packages installed that are affected by a vulnerability as referenced in the SUSE- SU-2026:1301-1 advisory.

    - CVE-2026-34352: Fixed permissions to prevent other users from observing the screen, or modifying what is     sent to the client. (bsc#1260871)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:1302-1 advisory.

    - CVE-2026-34352: Fixed permissions to prevent other users from observing the screen, or modifying what is     sent to the client. (bsc#1260871)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of tigervnc installed on the remote host is prior to 1.8.0-24. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3231 advisory.

    In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen     contents, or cause an application crash, because of incorrect permissions. (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-1537 advisory.

    In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen     contents, or cause an application crash, because of incorrect permissions. (CVE-2026-34352)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:1252-1 advisory.

    - CVE-2026-34352: Fixed permissions to prevent other users from observing the screen, or modifying what is     sent to the client. (bsc#1260871)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has packages installed that are affected by a vulnerability as referenced in the openSUSE- SU-2026:20465-1 advisory.

    - CVE-2026-34352: Fixed permissions to prevent other users from observing the screen, or modifying what is     sent to the client. (bsc#1260871)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen     contents, or cause an application crash, because of incorrect permissions. (CVE-2026-34352)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
316896	RHEL 9 : tigervnc (RHSA-2026:20575)	Nessus	Red Hat Local Security Checks	critical
316743	RHEL 9 : tigervnc (RHSA-2026:20576)	Nessus	Red Hat Local Security Checks	critical
316692	TencentOS Server 3: tigervnc (TSSA-2026:0377)	Nessus	Tencent Local Security Checks	critical
315581	RHEL 9 : tigervnc (RHSA-2026:19342)	Nessus	Red Hat Local Security Checks	critical
315129	Alibaba Cloud Linux 3 : 0108: tigervnc (ALINUX3-SA-2026:0108)	Nessus	Alibaba Cloud Linux Local Security Checks	critical
314164	MiracleLinux 8 : tigervnc-1.15.0-9.el8_10.ML.1 (AXSA:2026-592:02)	Nessus	Miracle Linux Local Security Checks	critical
313017	RockyLinux 8 : tigervnc (RLSA-2026:13414)	Nessus	Rocky Linux Local Security Checks	critical
312315	Oracle Linux 8 : tigervnc (ELSA-2026-13414)	Nessus	Oracle Linux Local Security Checks	critical
312262	AlmaLinux 8 : tigervnc (ALSA-2026:13414)	Nessus	Alma Linux Local Security Checks	critical
312088	RHEL 8 : tigervnc (RHSA-2026:13414)	Nessus	Red Hat Local Security Checks	critical
311834	MiracleLinux 9 : tigervnc-1.15.0-6.el9_7.1 (AXSA:2026-530:01)	Nessus	Miracle Linux Local Security Checks	critical
311079	AlmaLinux 9 : tigervnc (ALSA-2026:10739)	Nessus	Alma Linux Local Security Checks	critical
310566	RockyLinux 9 : tigervnc (RLSA-2026:10739)	Nessus	Rocky Linux Local Security Checks	critical
310546	Oracle Linux 9 : tigervnc (ELSA-2026-10739)	Nessus	Oracle Linux Local Security Checks	critical
310410	RHEL 9 : tigervnc (RHSA-2026:10739)	Nessus	Red Hat Local Security Checks	critical
306688	SUSE SLED15 / SLES15 Security Update : tigervnc (SUSE-SU-2026:1360-1)	Nessus	SuSE Local Security Checks	critical
306499	SUSE SLES15 Security Update : tigervnc (SUSE-SU-2026:1303-1)	Nessus	SuSE Local Security Checks	critical
306498	SUSE SLES12 Security Update : tigervnc (SUSE-SU-2026:1301-1)	Nessus	SuSE Local Security Checks	critical
306483	SUSE SLES15 Security Update : tigervnc (SUSE-SU-2026:1302-1)	Nessus	SuSE Local Security Checks	critical
306286	Amazon Linux 2 : tigervnc, --advisory ALAS2-2026-3231 (ALAS-2026-3231)	Nessus	Amazon Linux Local Security Checks	critical
306204	Amazon Linux 2023 : tigervnc, tigervnc-icons, tigervnc-license (ALAS2023-2026-1537)	Nessus	Amazon Linux Local Security Checks	critical
305987	SUSE SLES15 / openSUSE 15 Security Update : tigervnc (SUSE-SU-2026:1252-1)	Nessus	SuSE Local Security Checks	critical
305835	openSUSE 16 Security Update : tigervnc (openSUSE-SU-2026:20465-1)	Nessus	SuSE Local Security Checks	critical
303993	Linux Distros Unpatched Vulnerability : CVE-2026-34352	Nessus	Misc.	critical

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