Race condition in Linux kernel - CVE-2026-63971

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU138673

Race condition in Linux kernel - CVE-2026-63971

Published: July 20, 2026


Vulnerability identifier: #VU138673
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63971
CWE-ID: CWE-362
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a race condition in sctp_wait_for_connect() in the SCTP socket implementation when waiting for an association to reach established state while another thread peels off the association to a new socket. A local user can trigger association migration during this window to cause a denial of service.

Exploitation requires concurrent access from another thread while the socket lock is dropped and re-acquired.


Affected software

Linux kernel
openEuler
Ubuntu
python3-perf-debuginfo
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-headers
kernel-source
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
python3-perf
kernel-extra-modules
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-63971

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
python3-perf-debuginfo - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
bpftool - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
bpftool-debuginfo - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-debuginfo - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-debugsource - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-devel - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-headers - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-source - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-tools - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-tools-debuginfo - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-tools-devel - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
perf - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
perf-debuginfo - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
python3-perf - addressed in versions 5.10.0-331.0.0.232, 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins