A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw to send a specially crafted message that, when processed by the VNC server, would lead to a floating point exception, resulting in a denial of service.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2022:0108 advisory.

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

    CVE-2018-20337:
    There is a stack-based buffer overflow in the parse_makernote function of dcraw_common.cpp in LibRaw     0.19.1. Crafted input will lead to a denial of service or possibly unspecified other impact.

    CVE-2019-3825:
    A vulnerability was discovered in gdm before 3.31.4. When timed login is enabled in configuration, an     attacker could bypass the lock screen by selecting the timed login user and waiting for the timer to     expire, at which time they would gain access to the logged-in user's session.

    CVE-2019-3827:
    An incorrect permission check in the admin backend in gvfs before version 1.39.4 was found that allows     reading and modify arbitrary files by privileged users without asking for password when no authentication     agent is running. This vulnerability can be exploited by malicious programs running under privileges of     users belonging to the wheel group to further escalate its privileges by modifying system files without     user's knowledge. Successful exploitation requires uncommon system configuration.

    CVE-2019-12447:
    An issue was discovered in GNOME gvfs 1.29.4 through 1.41.2. daemon/gvfsbackendadmin.c mishandles file     ownership because setfsuid is not used.

    CVE-2019-12448:
    An issue was discovered in GNOME gvfs 1.29.4 through 1.41.2. daemon/gvfsbackendadmin.c has race conditions     because the admin backend doesn't implement query_info_on_read/write.

    CVE-2019-12449:
    An issue was discovered in GNOME gvfs 1.29.4 through 1.41.2. daemon/gvfsbackendadmin.c mishandles a file's     user and group ownership during move (and copy with G_FILE_COPY_ALL_METADATA) operations from admin:// to     file:// URIs, because root privileges are unavailable.

    CVE-2019-12795:
    daemon/gvfsdaemon.c in gvfsd from GNOME gvfs before 1.38.3, 1.40.x before 1.40.2, and 1.41.x before 1.41.3     opened a private D-Bus server socket without configuring an authorization rule. A local attacker could     connect to this server socket and issue D-Bus method calls.(Note that the server socket only accepts a     single connection, so the attacker would have to discover the server and connect to the socket before its     owner does.)

    CVE-2019-15690:
    ** RESERVED ** This candidate has been reserved by an organization or individual that will use it when     announcing a new security problem. When the candidate has been publicized, the details for this candidate     will be provided.

    CVE-2019-20839:
    libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.

    CVE-2020-14397:
    An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference.

    CVE-2020-14405:
    An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat     size.

    CVE-2020-15503:
    LibRaw before 0.20-RC1 lacks a thumbnail size range check. This affects decoders/unpack_thumb.cpp,     postprocessing/mem_image.cpp, and utils/thumb_utils.cpp. For example,     malloc(sizeof(libraw_processed_image_t)+T.tlength) occurs without validating T.tlength.

    CVE-2020-25708:
    A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service.

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

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

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

The remote Rocky Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2021:1811 advisory.

  - An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized     memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function. (CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.
    (CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference. (CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat     size. (CVE-2020-14405)

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

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

The remote Debian 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3125 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-3125-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                    Thorsten Alteholz     September 30, 2022                            https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : libvncserver     Version        : 0.9.11+dfsg-1.3+deb10u5     CVE ID         : CVE-2020-25708 CVE-2020-29260


    Two issues have been found in libvncserver, a library to write one's own     VNC server.


    CVE-2020-25708

        Due to some missing checks, a divide by zero could happen, which could         result in a denial of service.

    CVE-2020-29260

        Due to a memory leak in function rfbClientCleanup() a remote attacker         might be able to cause a denial of service.



    For Debian 10 buster, these problems have been fixed in version     0.9.11+dfsg-1.3+deb10u5.

    We recommend that you upgrade your libvncserver packages.

    For the detailed security status of libvncserver please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/libvncserver

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian 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 NewStart CGSL host, running version MAIN 6.02, has libvncserver packages installed that are affected by multiple vulnerabilities:

  - An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized     memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function. (CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.
    (CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference. (CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat     size. (CVE-2020-14405)

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

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-2021:1811 advisory.

  - An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized     memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function. (CVE-2018-21247)

  - libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.
    (CVE-2019-20839)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncserver/rfbregion.c has a NULL pointer     dereference. (CVE-2020-14397)

  - An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat     size. (CVE-2020-14405)

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

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 SLES11 host has a package installed that is affected by a vulnerability as referenced in the SUSE- SU-2020:14549-1 advisory.

  - A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw     to send a specially crafted message that, when processed by the VNC server, would lead to a floating point     exception, resulting in a denial of service. (CVE-2020-25708)

Note that Nessus has not tested for this issue 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-2021-1811 advisory.

    - Fix CVE-2020-25708       Resolves: #1898078
    - Fix CVE-2019-20839       Resolves: #1851032
    - Fix CVE-2018-21247       Resolves: #1852516
    - Fix CVE-2020-14405       Resolves: #1860527

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 CentOS Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the CESA-2021:1811 advisory.

  - libvncserver: uninitialized memory contents are vulnerable to Information Leak (CVE-2018-21247)

  - libvncserver: buffer overflow in ConnectClientToUnixSock() (CVE-2019-20839)

  - libvncserver: libvncserver/rfbregion.c has a NULL pointer dereference (CVE-2020-14397)

  - libvncserver: libvncclient/rfbproto.c does not limit TextChat size (CVE-2020-14405)

  - libvncserver: libvncserver/rfbserver.c has a divide by zero which could result in DoS (CVE-2020-25708)

Note that Nessus has not tested for this issue 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-2021:1811 advisory.

    LibVNCServer is a C library that enables you to implement VNC server functionality into own programs.

    Security Fix(es):

    * libvncserver: uninitialized memory contents are vulnerable to Information Leak (CVE-2018-21247)

    * libvncserver: buffer overflow in ConnectClientToUnixSock() (CVE-2019-20839)

    * libvncserver: libvncserver/rfbregion.c has a NULL pointer dereference (CVE-2020-14397)

    * libvncserver: libvncclient/rfbproto.c does not limit TextChat size (CVE-2020-14405)

    * libvncserver: libvncserver/rfbserver.c has a divide by zero which could result in DoS (CVE-2020-25708)

    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.

    Additional Changes:

    For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.4 Release Notes     linked from 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.

According to the version of the libvncserver package installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - A divide by zero issue was found to occur in     libvncserver-0.9.12. A malicious client could use this     flaw to send a specially crafted message that, when     processed by the VNC server, would lead to a floating     point exception, resulting in a denial of     service.(CVE-2020-25708)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the libvncserver package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - Heap-based buffer overflow in ultra.c in LibVNCClient     in LibVNCServer before 0.9.11 allows remote servers to     cause a denial of service (application crash) or     possibly execute arbitrary code via a crafted     FramebufferUpdate message with the Ultra type tile,     such that the LZO payload decompressed length exceeds     what is specified by the tile     dimensions.(CVE-2016-9942)

  - It was discovered that websockets.c in LibVNCServer     prior to 0.9.12 did not properly decode certain     WebSocket frames. A malicious attacker could exploit     this by sending specially crafted WebSocket frames to a     server, causing a heap-based buffer     overflow.(CVE-2017-18922)

  - LibVNC commit before     d01e1bb4246323ba6fcee3b82ef1faa9b1dac82a contains a     memory leak (CWE-655) in VNC server code, which allow     an attacker to read stack memory and can be abused for     information disclosure. Combined with another     vulnerability, it can be used to leak stack memory and     bypass ASLR. This attack appear to be exploitable via     network connectivity. These vulnerabilities have been     fixed in commit     d01e1bb4246323ba6fcee3b82ef1faa9b1dac82a.(CVE-2019-1568     1)

  - A divide by zero issue was found to occur in     libvncserver-0.9.12. A malicious client could use this     flaw to send a specially crafted message that, when     processed by the VNC server, would lead to a floating     point exception, resulting in a denial of     service.(CVE-2020-25708)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the libvncserver package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - A divide by zero issue was found to occur in     libvncserver-0.9.12. A malicious client could use this     flaw to send a specially crafted message that, when     processed by the VNC server, would lead to a floating     point exception, resulting in a denial of     service.(CVE-2020-25708)

  - An issue was discovered in LibVNCServer before 0.9.13.
    libvncserver/ws_decode.c can lead to a crash because of     unaligned accesses in     hybiReadAndDecode.(CVE-2019-20840)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for LibVNCServer fixes the following issues :

CVE-2020-25708 [bsc#1178682], libvncserver/rfbserver.c has a divide by zero which could result in DoS

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for LibVNCServer fixes the following issues :

  - CVE-2020-25708 [bsc#1178682], libvncserver/rfbserver.c     has a divide by zero which could result in DoS

This update was imported from the SUSE:SLE-15:Update update project.

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-4636-1 advisory.

    It was discovered that LibVNCServer incorrectly handled certain internals. An attacker could possibly use     this issue to cause a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS and     Ubuntu 20.04 LTS.

    Vino package ships with a LibVNCServer source and all listed releases were affected for this package.

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

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

An issue has been found in libvncserver, an API to write one's own VNC server. Due to some missing checks, a divide by zero could happen, which could result in a denial of service.

For Debian 9 stretch, this problem has been fixed in version 0.9.11+dfsg-1.3~deb9u6.

We recommend that you upgrade your libvncserver packages.

For the detailed security status of libvncserver please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/libvncserver

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
236504	Alibaba Cloud Linux 3 : 0108: GNOME (ALINUX3-SA-2022:0108)	Nessus	Alibaba Cloud Linux Local Security Checks	high
229947	Linux Distros Unpatched Vulnerability : CVE-2020-25708	Nessus	Misc.	high
184742	Rocky Linux 8 : libvncserver (RLSA-2021:1811)	Nessus	Rocky Linux Local Security Checks	high
165593	Debian dla-3125 : libvncclient1 - security update	Nessus	Debian Local Security Checks	high
160737	NewStart CGSL MAIN 6.02 : libvncserver Multiple Vulnerabilities (NS-SA-2022-0048)	Nessus	NewStart CGSL Local Security Checks	high
157648	AlmaLinux 8 : libvncserver (ALSA-2021:1811)	Nessus	Alma Linux Local Security Checks	high
150527	SUSE SLES11 Security Update : LibVNCServer (SUSE-SU-2020:14549-1)	Nessus	SuSE Local Security Checks	high
149968	Oracle Linux 8 : libvncserver (ELSA-2021-1811)	Nessus	Oracle Linux Local Security Checks	high
149728	CentOS 8 : libvncserver (CESA-2021:1811)	Nessus	CentOS Local Security Checks	high
149663	RHEL 8 : libvncserver (RHSA-2021:1811)	Nessus	Red Hat Local Security Checks	high
148083	EulerOS 2.0 SP5 : libvncserver (EulerOS-SA-2021-1688)	Nessus	Huawei Local Security Checks	high
146731	EulerOS 2.0 SP2 : libvncserver (EulerOS-SA-2021-1321)	Nessus	Huawei Local Security Checks	critical
145732	EulerOS 2.0 SP8 : libvncserver (EulerOS-SA-2021-1153)	Nessus	Huawei Local Security Checks	high
145206	EulerOS 2.0 SP3 : libvncserver (EulerOS-SA-2021-1091)	Nessus	Huawei Local Security Checks	critical
143764	SUSE SLES12 Security Update : LibVNCServer (SUSE-SU-2020:3550-1)	Nessus	SuSE Local Security Checks	high
143668	SUSE SLED15 / SLES15 Security Update : LibVNCServer (SUSE-SU-2020:3515-1)	Nessus	SuSE Local Security Checks	high
143345	openSUSE Security Update : LibVNCServer (openSUSE-2020-2025)	Nessus	SuSE Local Security Checks	high
143328	openSUSE Security Update : LibVNCServer (openSUSE-2020-2097)	Nessus	SuSE Local Security Checks	high
142998	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : LibVNCServer, Vino vulnerability (USN-4636-1)	Nessus	Ubuntu Local Security Checks	high
142924	Debian DLA-2451-1 : libvncserver security update	Nessus	Debian Local Security Checks	high

Detections

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CVE-2020-25708

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