SB20260816154 - Use-after-free in Linux kernel ipv4

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-74562)

CWE-ID: CWE-416 - Use After Free

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 a use-after-free in fib6_check_nh_list() and __nexthop_replace_notify() when walking nh->f6i_list during nexthop replace operations concurrent with IPv6 route deletion. A local user can trigger concurrent route update and delete activity to cause a denial of service.

The issue occurs because the list walks are performed without holding nh->lock while IPv6 route operations can unlink and free fib6_info entries under that lock.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/072cd1f21819dedd2252e704d255de3b0cfc61a7
• https://git.kernel.org/stable/c/bb2b072c619c1f741a6234257050f72005dc63ef