Upstream information

CVE-2026-63913 at MITRE

Description

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.

SUSE information

Overall state of this security issue: Pending

This issue is currently rated as having moderate severity.

CVSS v3 Scores
CVSS detail CNA (NVD) Linux Kernel CNA SUSE
Base Score 8.2 8.2 5.9
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network Network Network
Attack Complexity Low Low High
Privileges Required None None None
User Interaction None None None
Scope Unchanged Unchanged Unchanged
Confidentiality Impact None None None
Integrity Impact Low Low None
Availability Impact High High High
CVSSv3 Version 3.1 3.1 3.1
CVSS v4 Scores
CVSS detail SUSE
Base Score 8.2
Vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Attack Vector Network
Attack Complexity High
Attack Requirements Present
Privileges Required None
User Interaction None
Vulnerable System Confidentiality Impact None
Vulnerable System Integrity Impact None
Vulnerable System Availability Impact High
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
CVSSv4 Version 4.0

Note from the SUSE Security Team on the kernel-default package

SUSE will no longer fix all CVEs in the Linux Kernel anymore, but declare some bug classes as won't fix. Please refer to TID 21496 for more details.

SUSE Bugzilla entry: 1272890 [NEW]

SUSE Security Advisories:

List of released packages

Product(s) Fixed package version(s) References
SUSE Liberty Linux 8
  • bpftool >= 4.18.0-553.158.1.el8_10
  • kernel >= 4.18.0-553.158.1.el8_10
  • kernel-abi-stablelists >= 4.18.0-553.158.1.el8_10
  • kernel-core >= 4.18.0-553.158.1.el8_10
  • kernel-cross-headers >= 4.18.0-553.158.1.el8_10
  • kernel-debug >= 4.18.0-553.158.1.el8_10
  • kernel-debug-core >= 4.18.0-553.158.1.el8_10
  • kernel-debug-devel >= 4.18.0-553.158.1.el8_10
  • kernel-debug-modules >= 4.18.0-553.158.1.el8_10
  • kernel-debug-modules-extra >= 4.18.0-553.158.1.el8_10
  • kernel-devel >= 4.18.0-553.158.1.el8_10
  • kernel-doc >= 4.18.0-553.158.1.el8_10
  • kernel-headers >= 4.18.0-553.158.1.el8_10
  • kernel-modules >= 4.18.0-553.158.1.el8_10
  • kernel-modules-extra >= 4.18.0-553.158.1.el8_10
  • kernel-tools >= 4.18.0-553.158.1.el8_10
  • kernel-tools-libs >= 4.18.0-553.158.1.el8_10
  • kernel-tools-libs-devel >= 4.18.0-553.158.1.el8_10
  • perf >= 4.18.0-553.158.1.el8_10
  • python3-perf >= 4.18.0-553.158.1.el8_10
 Patchnames:
RHSA-2026:59821 (x86_64)

Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Desktop 15 SP7 kernel-default Affected
SUSE Linux Enterprise Desktop 15 SP7 kernel-source Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 kernel-default Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 kernel-source Affected
SUSE Linux Enterprise High Availability Extension 16.0 kernel-default Affected
SUSE Linux Enterprise High Availability Extension 16.0 kernel-source Affected
SUSE Linux Enterprise High Availability Extension 16.1 kernel-default Affected
SUSE Linux Enterprise High Availability Extension 16.1 kernel-source Affected
SUSE Linux Enterprise Live Patching 15 SP7 kernel-default Affected
SUSE Linux Enterprise Live Patching 15 SP7 kernel-source Affected
SUSE Linux Enterprise Micro 5.3 kernel-default Affected
SUSE Linux Enterprise Micro 5.3 kernel-rt Affected
SUSE Linux Enterprise Micro 5.3 kernel-source Affected
SUSE Linux Enterprise Micro 5.3 kernel-source-rt Affected
SUSE Linux Enterprise Micro 5.4 kernel-default Affected
SUSE Linux Enterprise Micro 5.4 kernel-rt Affected
SUSE Linux Enterprise Micro 5.4 kernel-source Affected
SUSE Linux Enterprise Micro 5.4 kernel-source-rt Affected
SUSE Linux Enterprise Micro 5.5 kernel-default Affected
SUSE Linux Enterprise Micro 5.5 kernel-source Affected
SUSE Linux Enterprise Micro 5.5 kernel-source-rt Affected
SUSE Linux Enterprise Module for Basesystem 15 SP7 kernel-default Affected
SUSE Linux Enterprise Module for Basesystem 15 SP7 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP7 kernel-default Affected
SUSE Linux Enterprise Module for Development Tools 15 SP7 kernel-source Affected
SUSE Linux Enterprise Module for Legacy 15 SP7 kernel-default Affected
SUSE Linux Enterprise Module for Legacy 15 SP7 kernel-source Affected
SUSE Linux Enterprise Module for Public Cloud 15 SP7 kernel-default Affected
SUSE Linux Enterprise Module for Public Cloud 15 SP7 kernel-source Affected
SUSE Linux Enterprise Real Time 15 SP7 kernel-source-rt Affected
SUSE Linux Enterprise Server 15 SP7 kernel-default Affected
SUSE Linux Enterprise Server 15 SP7 kernel-source Affected
SUSE Linux Enterprise Server 16.0 kernel-default Affected
SUSE Linux Enterprise Server 16.0 kernel-source Affected
SUSE Linux Enterprise Server 16.1 kernel-default Affected
SUSE Linux Enterprise Server 16.1 kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP7 kernel-default Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP7 kernel-source Affected
SUSE Linux Enterprise Server for SAP applications 16.0 kernel-default Affected
SUSE Linux Enterprise Server for SAP applications 16.0 kernel-source Affected
SUSE Linux Enterprise Server for SAP applications 16.1 kernel-default Affected
SUSE Linux Enterprise Server for SAP applications 16.1 kernel-source Affected
SUSE Linux Enterprise Workstation Extension 15 SP7 kernel-default Affected
SUSE Linux Enterprise Workstation Extension 15 SP7 kernel-source Affected
SUSE Linux Micro 6.0 kernel-default Affected
SUSE Linux Micro 6.0 kernel-source Affected
SUSE Linux Micro 6.0 kernel-source-rt Affected
SUSE Linux Micro 6.1 kernel-default Affected
SUSE Linux Micro 6.1 kernel-source Affected
SUSE Linux Micro 6.1 kernel-source-rt Affected
SUSE Linux Micro 6.2 kernel-default Affected
SUSE Linux Micro 6.2 kernel-source Affected
SUSE Linux Micro Extras 6.0 kernel-default Affected
SUSE Linux Micro Extras 6.0 kernel-source Affected
SUSE Linux Micro Extras 6.0 kernel-source-rt Affected
SUSE Linux Micro Extras 6.1 kernel-default Affected
SUSE Linux Micro Extras 6.1 kernel-source Affected
SUSE Real Time Module 15 SP7 kernel-source-rt Affected
openSUSE Leap 16.0 kernel-source Affected
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-default Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP5 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-source Affected
SUSE Linux Enterprise Live Patching 12 SP5 kernel-default Affected
SUSE Linux Enterprise Live Patching 12 SP5 kernel-source Affected
SUSE Linux Enterprise Live Patching 15 SP4 kernel-default Affected
SUSE Linux Enterprise Live Patching 15 SP4 kernel-source Affected
SUSE Linux Enterprise Live Patching 15 SP5 kernel-default Affected
SUSE Linux Enterprise Live Patching 15 SP5 kernel-source Affected
SUSE Linux Enterprise Module for Basesystem 15 SP4 kernel-source Affected
SUSE Linux Enterprise Module for Basesystem 15 SP5 kernel-source Affected
SUSE Linux Enterprise Module for Basesystem 15 SP6 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP4 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP5 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP6 kernel-source Affected
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-default Not affected
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-source Not affected
SUSE Linux Enterprise Server 12 SP5 kernel-source Affected
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-default Affected
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-source Affected
SUSE Linux Enterprise Server 15 SP4 kernel-source Affected
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-default Affected
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-source Affected
SUSE Linux Enterprise Server 15 SP5 kernel-source Affected
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-default Affected
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-source Affected
SUSE Linux Enterprise Server 15 SP6 kernel-source Affected
SUSE Linux Enterprise Server 15 SP6-LTSS kernel-default Affected
SUSE Linux Enterprise Server 15 SP6-LTSS kernel-source Affected
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-default Affected
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-default Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-default Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-default Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-source Affected
Products past their end of life and not receiving proactive updates anymore.
SUSE CaaS Platform 4.0 kernel-source Affected
SUSE Enterprise Storage 6 kernel-source Affected
SUSE Enterprise Storage 7 kernel-source Affected
SUSE Enterprise Storage 7.1 kernel-source Affected
SUSE Linux Enterprise Desktop 11 SP4 kernel-source Not affected
SUSE Linux Enterprise Desktop 15 SP1 kernel-source Affected
SUSE Linux Enterprise Desktop 15 SP2 kernel-source Affected
SUSE Linux Enterprise Desktop 15 SP3 kernel-source Affected
SUSE Linux Enterprise Desktop 15 SP4 kernel-source Affected
SUSE Linux Enterprise Desktop 15 SP5 kernel-source Affected
SUSE Linux Enterprise Desktop 15 SP6 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP1 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP2 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP3 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP4 kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS kernel-source Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-source Affected
SUSE Linux Enterprise Micro 5.0 kernel-default Affected
SUSE Linux Enterprise Micro 5.1 kernel-default Affected
SUSE Linux Enterprise Micro 5.2 kernel-default Affected
SUSE Linux Enterprise Micro 5.2 kernel-source Affected
SUSE Linux Enterprise Module for Basesystem 15 SP1 kernel-source Affected
SUSE Linux Enterprise Module for Basesystem 15 SP2 kernel-source Affected
SUSE Linux Enterprise Module for Basesystem 15 SP3 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP1 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP2 kernel-source Affected
SUSE Linux Enterprise Module for Development Tools 15 SP3 kernel-source Affected
SUSE Linux Enterprise Real Time 15 SP2 kernel-source Affected
SUSE Linux Enterprise Real Time 15 SP3 kernel-source Affected
SUSE Linux Enterprise Real Time 15 SP4 kernel-source Affected
SUSE Linux Enterprise Real Time 15 SP4 kernel-source-rt Affected
SUSE Linux Enterprise Real Time 15 SP5 kernel-source-rt Affected
SUSE Linux Enterprise Server 11 SP4 kernel-source Not affected
SUSE Linux Enterprise Server 11 SP4-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 15 SP1 kernel-source Affected
SUSE Linux Enterprise Server 15 SP1-BCL kernel-source Affected
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-default Affected
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-source Affected
SUSE Linux Enterprise Server 15 SP2 kernel-source Affected
SUSE Linux Enterprise Server 15 SP2-BCL kernel-source Affected
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-default Affected
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-source Affected
SUSE Linux Enterprise Server 15 SP3 kernel-source Affected
SUSE Linux Enterprise Server 15 SP3-BCL kernel-source Affected
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-default Affected
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP1 kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP2 kernel-source Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP3 kernel-source Affected
SUSE Manager Proxy 4.0 kernel-source Affected
SUSE Manager Proxy 4.1 kernel-source Affected
SUSE Manager Proxy 4.2 kernel-source Affected
SUSE Manager Proxy 4.3 kernel-source Affected
SUSE Manager Proxy LTS 4.3 kernel-source Affected
SUSE Manager Retail Branch Server 4.0 kernel-source Affected
SUSE Manager Retail Branch Server 4.1 kernel-source Affected
SUSE Manager Retail Branch Server 4.2 kernel-source Affected
SUSE Manager Retail Branch Server 4.3 kernel-source Affected
SUSE Manager Retail Branch Server LTS 4.3 kernel-source Affected
SUSE Manager Server 4.0 kernel-source Affected
SUSE Manager Server 4.1 kernel-source Affected
SUSE Manager Server 4.2 kernel-source Affected
SUSE Manager Server 4.3 kernel-source Affected
SUSE Manager Server LTS 4.3 kernel-source Affected
SUSE Real Time Module 15 SP4 kernel-source-rt Affected
SUSE Real Time Module 15 SP5 kernel-source-rt Affected
openSUSE Leap 15.3 kernel-source Affected
openSUSE Leap 15.4 kernel-source Affected
openSUSE Leap 15.4 kernel-source-rt Affected
openSUSE Leap 15.5 kernel-source Affected
openSUSE Leap 15.5 kernel-source-rt Affected
openSUSE Leap 15.6 kernel-source Affected

SUSE Timeline for this CVE

CVE page created: Mon Jul 20 11:50:56 2026
CVE page last modified: Fri Sep 4 11:41:38 2026