SB20260812227 - Improper locking in Linux kernel ipv6

Description

This security bulletin contains information about 1 vulnerability.

1) Improper locking (CVE-ID: CVE-2026-68296)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/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 improper lock management in GRE tunnel initialization in net/ipv4/ip_gre.c and net/ipv6/ip6_gre.c when transmitting through GRE, GRETAP, or ip6gre tunnels configured with SEQ or CSUM encapsulation. A local user can trigger network transmission through a specially configured tunnel to cause a denial of service.

The issue can lead to an ABBA deadlock involving _xmit_lock acquisition on the underlay device.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/15a1c5f2ed2eeb3daad8d5766fd506aeda4710f3
• https://git.kernel.org/stable/c/2bffe379023512d280337c70faeb6a8cc435db5e
• https://git.kernel.org/stable/c/675ed582c1aa4d919dd535490de08c015005c653
• https://git.kernel.org/stable/c/9f948e9aede9678f4103457daf2bc9dd54c65a06