SB20260720263 - Race condition in Linux kernel handshake

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-63978)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 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]

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

The vulnerability exists due to a race condition in net/handshake request draining during net namespace exit when canceling pending handshake requests concurrently with namespace teardown. A local user can trigger concurrent handshake request cancellation and net namespace destruction to cause a denial of service.

The issue affects pending handshake requests that have not yet been accepted and can result in list corruption or a request being freed while still linked on the drain loop's local list.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/8c35539db0ab0bfa1ea44efab00b053261a69469
• https://git.kernel.org/stable/c/9ec20c9a5a04f2c3f1cf65d21f886d7aaa6189cd
• https://git.kernel.org/stable/c/ea5fe6a73ca57e5150b8a38b341aef2636eb72f0