In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check An unintended behavior in the TCP conntrack state machine allows a connection to be forced into the CLOSE state using an RST packet with an invalid sequence number. Specifically, after a SYN packet is observed, an RST with an invalid SEQ can transition the conntrack entry to TCP_CONNTRACK_CLOSE, regardless of whether the RST corresponds to the expected reply direction. The relevant code path assumes the RST is a response to an outgoing SYN, but does not validate packet direction or ensure that a matching SYN was actually sent in the opposite direction. As a result, a crafted packet sequence consisting of a SYN followed by an invalid-sequence RST can prematurely terminate an active NAT entry. This makes connection teardown easier than intended. So, tighten the state transition logic to ensure that RST-triggered CLOSE transitions only occur when the RST is a valid response to a previously observed SYN in the correct direction.

The remote RockyLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:59737 advisory.

    * kernel: sctp: purge outqueue on stale COOKIE-ECHO handling (CVE-2026-52924)

    * kernel: scsi: target: iscsi: Validate CHAP_R length before base64 decode (CVE-2026-63886)

    * kernel: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check     (CVE-2026-63913)

    * kernel: i2c: stub: Reject I2C block transfers with invalid length (CVE-2026-64191)

    * kernel: netfilter: ipset: fix race between dump and ip_set_list resize (CVE-2026-64189)

    * kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (CVE-2026-64320)

    * kernel: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CVE-2026-64277)

    * kernel: Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CVE-2026-64276)

    Bug Fix(es) and Enhancement(s):

    * [Rocky Linux-RT] usb_hub_wq items may run on isolated+nohz_full cores (JIRA:Rocky Linux-178088)

    * SELinux TCP/MPTCP connect check bypass via TCP Fast Open [rhel-8.10.z] (JIRA:Rocky Linux-222800)

    * ss core dumped when there is an SCTP session [rhel-8.10.z] (JIRA:Rocky Linux-212400)

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-2026-59821 advisory.

    - nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (Maurizio Lombardi) [RHEL-219613]     {CVE-2026-64320}
    - i2c: stub: Reject I2C block transfers with invalid length (CKI Backport Bot) [RHEL-232120]     {CVE-2026-64191}
    - scsi: target: Fix hexadecimal CHAP_I handling (CKI Backport Bot) [RHEL-231660] {CVE-2026-63886}
    - scsi: target: iscsi: Validate CHAP_R length before base64 decode (CKI Backport Bot) [RHEL-231660]     {CVE-2026-63886}
    - Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CKI Backport Bot) [RHEL-231447]     {CVE-2026-64277}
    - Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CKI Backport Bot) [RHEL-230251]     {CVE-2026-64276}
    - netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check (CKI Backport     Bot) [RHEL-229797] {CVE-2026-63913}
    - netfilter: ipset: fix race between dump and ip_set_list resize (CKI Backport Bot) [RHEL-227676]     {CVE-2026-64189}

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 RockyLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:59821 advisory.

    * kernel: sctp: purge outqueue on stale COOKIE-ECHO handling (CVE-2026-52924)

    * kernel: scsi: target: iscsi: Validate CHAP_R length before base64 decode (CVE-2026-63886)

    * kernel: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check     (CVE-2026-63913)

    * kernel: i2c: stub: Reject I2C block transfers with invalid length (CVE-2026-64191)

    * kernel: netfilter: ipset: fix race between dump and ip_set_list resize (CVE-2026-64189)

    * kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (CVE-2026-64320)

    * kernel: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CVE-2026-64277)

    * kernel: Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CVE-2026-64276)

    Bug Fix(es) and Enhancement(s):

    * ss core dumped when there is an SCTP session [rhel-8.10.z] (JIRA:Rocky Linux-212400)

    * SELinux TCP/MPTCP connect check bypass via TCP Fast Open [rhel-8.10.z] (JIRA:Rocky Linux-222800)

    * [Rocky Linux-RT] usb_hub_wq items may run on isolated+nohz_full cores (JIRA:Rocky Linux-178088)

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 AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:59737 advisory.

    * kernel: sctp: purge outqueue on stale COOKIE-ECHO handling (CVE-2026-52924)
      * kernel: scsi: target: iscsi: Validate CHAP_R length before base64 decode (CVE-2026-63886)
      * kernel: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check     (CVE-2026-63913)
      * kernel: i2c: stub: Reject I2C block transfers with invalid length (CVE-2026-64191)
      * kernel: netfilter: ipset: fix race between dump and ip_set_list resize (CVE-2026-64189)
      * kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (CVE-2026-64320)
      * kernel: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CVE-2026-64277)
      * kernel: Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CVE-2026-64276)


    Bug Fix(es) and Enhancement(s):

      * [AlmaLinux-RT] usb_hub_wq items may run on isolated+nohz_full cores (JIRA:AlmaLinux-178088)
      * SELinux TCP/MPTCP connect check bypass via TCP Fast Open [almalinux-8.10.z] (JIRA:AlmaLinux-222800)
      * ss core dumped when there is an SCTP session [almalinux-8.10.z] (JIRA:AlmaLinux-212400)

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 AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:59821 advisory.

    * kernel: sctp: purge outqueue on stale COOKIE-ECHO handling (CVE-2026-52924)
      * kernel: scsi: target: iscsi: Validate CHAP_R length before base64 decode (CVE-2026-63886)
      * kernel: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check     (CVE-2026-63913)
      * kernel: i2c: stub: Reject I2C block transfers with invalid length (CVE-2026-64191)
      * kernel: netfilter: ipset: fix race between dump and ip_set_list resize (CVE-2026-64189)
      * kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (CVE-2026-64320)
      * kernel: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CVE-2026-64277)
      * kernel: Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CVE-2026-64276)


    Bug Fix(es) and Enhancement(s):

      * ss core dumped when there is an SCTP session [almalinux-8.10.z] (JIRA:AlmaLinux-212400)
      * SELinux TCP/MPTCP connect check bypass via TCP Fast Open [almalinux-8.10.z] (JIRA:AlmaLinux-222800)
      * [AlmaLinux-RT] usb_hub_wq items may run on isolated+nohz_full cores (JIRA:AlmaLinux-178088)

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-2026:59821 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux operating system.

    Security Fix(es):

    * kernel: sctp: purge outqueue on stale COOKIE-ECHO handling (CVE-2026-52924)

    * kernel: scsi: target: iscsi: Validate CHAP_R length before base64 decode (CVE-2026-63886)

    * kernel: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check     (CVE-2026-63913)

    * kernel: i2c: stub: Reject I2C block transfers with invalid length (CVE-2026-64191)

    * kernel: netfilter: ipset: fix race between dump and ip_set_list resize (CVE-2026-64189)

    * kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (CVE-2026-64320)

    * kernel: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CVE-2026-64277)

    * kernel: Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CVE-2026-64276)

    Bug Fix(es) and Enhancement(s):

    * ss core dumped when there is an SCTP session [rhel-8.10.z] (JIRA:RHEL-212400)

    * SELinux TCP/MPTCP connect check bypass via TCP Fast Open [rhel-8.10.z] (JIRA:RHEL-222800)

    * [RHEL-RT] usb_hub_wq items may run on isolated+nohz_full cores (JIRA:RHEL-178088)

    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 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:59737 advisory.

    The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with     extremely high determinism requirements.

    Security Fix(es):

    * kernel: sctp: purge outqueue on stale COOKIE-ECHO handling (CVE-2026-52924)

    * kernel: scsi: target: iscsi: Validate CHAP_R length before base64 decode (CVE-2026-63886)

    * kernel: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check     (CVE-2026-63913)

    * kernel: i2c: stub: Reject I2C block transfers with invalid length (CVE-2026-64191)

    * kernel: netfilter: ipset: fix race between dump and ip_set_list resize (CVE-2026-64189)

    * kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page (CVE-2026-64320)

    * kernel: Input: synaptics-rmi4 - bound the F3A keymap to the GPIO count (CVE-2026-64277)

    * kernel: Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count (CVE-2026-64276)

    Bug Fix(es) and Enhancement(s):

    * [RHEL-RT] usb_hub_wq items may run on isolated+nohz_full cores (JIRA:RHEL-178088)

    * SELinux TCP/MPTCP connect check bypass via TCP Fast Open [rhel-8.10.z] (JIRA:RHEL-222800)

    * ss core dumped when there is an SCTP session [rhel-8.10.z] (JIRA:RHEL-212400)

    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 Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-099988 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check

    An unintended behavior in the TCP conntrack state machine allows a     connection to be forced into the CLOSE state using an RST packet with an     invalid sequence number.

    Specifically, after a SYN packet is observed, an RST with an invalid SEQ     can transition the conntrack entry to TCP_CONNTRACK_CLOSE, regardless of     whether the RST corresponds to the expected reply direction. The relevant     code path assumes the RST is a response to an outgoing SYN, but does not     validate packet direction or ensure that a matching SYN was actually sent     in the opposite direction.

    As a result, a crafted packet sequence consisting of a SYN followed by an     invalid-sequence RST can prematurely terminate an active NAT entry. This     makes connection teardown easier than intended.

    So, tighten the state transition logic to ensure that RST-triggered     CLOSE transitions only occur when the RST is a valid response to a     previously observed SYN in the correct direction.

Tenable has extracted the preceding description block directly from the Unity Linux 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 update of the linux package has been released.

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

  - netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check An unintended     behavior in the TCP conntrack state machine allows a connection to be forced into the CLOSE state using an     RST packet with an invalid sequence number. Specifically, after a SYN packet is observed, an RST with an     invalid SEQ can transition the conntrack entry to TCP_CONNTRACK_CLOSE, regardless of whether the RST     corresponds to the expected reply direction. The relevant code path assumes the RST is a response to an     outgoing SYN, but does not validate packet direction or ensure that a matching SYN was actually sent in     the opposite direction. As a result, a crafted packet sequence consisting of a SYN followed by an invalid-     sequence RST can prematurely terminate an active NAT entry. This makes connection teardown easier than     intended. So, tighten the state transition logic to ensure that RST-triggered CLOSE transitions only occur     when the RST is a valid response to a previously observed SYN in the correct direction. (CVE-2026-63913)

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

ID	Name	Product	Family	Type	Severity
341091	RockyLinux 8 : kernel-rt (RLSA-2026:59737)	Nessus	Rocky Linux Local Security Checks	Local	critical
341072	Oracle Linux 8 : kernel (ELSA-2026-59821)	Nessus	Oracle Linux Local Security Checks	Local	critical
341047	RockyLinux 8 : kernel (RLSA-2026:59821)	Nessus	Rocky Linux Local Security Checks	Local	critical
340744	AlmaLinux 8 : kernel-rt (ALSA-2026:59737)	Nessus	Alma Linux Local Security Checks	Local	critical
340718	AlmaLinux 8 : kernel (ALSA-2026:59821)	Nessus	Alma Linux Local Security Checks	Local	critical
340681	Ubuntu 24.04 LTS / 26.04 LTS / Pro Realtime 24.04 LTS : Linux kernel (NVIDIA) vulnerabilities (USN-8663-1)	Nessus	Ubuntu Local Security Checks	Local	high
340045	Ubuntu 26.04 LTS : Linux kernel (NVIDIA BaseOS) vulnerabilities (USN-8664-1)	Nessus	Ubuntu Local Security Checks	Local	high
339923	RHEL 8 : kernel (RHSA-2026:59821)	Nessus	Red Hat Local Security Checks	Local	critical
339689	RHEL 8 : kernel-rt (RHSA-2026:59737)	Nessus	Red Hat Local Security Checks	Local	critical
336607	Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099988)	Nessus	Unity Linux Local Security Checks	Local	high
333941	Photon OS 5.0: Linux PHSA-2026-5.0-92-0926	Nessus	PhotonOS Local Security Checks	Local	high
333762	Photon OS 5.0: Linux PHSA-2026-5.0-92-0895	Nessus	PhotonOS Local Security Checks	Local	high
329326	Photon OS 5.0: Linux PHSA-2026-5.0-0926	Nessus	PhotonOS Local Security Checks	Local	high
328499	Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.15-2026-110 (ALASKERNEL-5.15-2026-110)	Nessus	Amazon Linux Local Security Checks	Local	medium
328493	Amazon Linux 2023 : bpftool6.12, kernel6.12, kernel6.12-devel (ALAS2023-2026-1968)	Nessus	Amazon Linux Local Security Checks	Local	high
328074	Linux Distros Unpatched Vulnerability : CVE-2026-63913	Nessus	Misc.	Local	high
327380	Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1924)	Nessus	Amazon Linux Local Security Checks	Local	high
325574	Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.10-2026-124 (ALASKERNEL-5.10-2026-124)	Nessus	Amazon Linux Local Security Checks	Local	high
322944	Photon OS 5.0: Linux PHSA-2026-5.0-0895	Nessus	PhotonOS Local Security Checks	Local	high
322087	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1881)	Nessus	Amazon Linux Local Security Checks	Local	high

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CVE-2026-63913

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