SB20260815339 - NULL pointer dereference in Linux kernel afs

Description

This security bulletin contains information about 1 vulnerability.

1) NULL pointer dereference (CVE-ID: CVE-2026-72377)

CWE-ID: CWE-476 - NULL Pointer Dereference

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 attacker to cause a denial of service.

The vulnerability exists due to a null pointer dereference in the AFS symlink and mountpoint folio release handling when memory management code attempts to release folios for AFS symlinks or mountpoints without buffer_heads. A local attacker can trigger folio release on a crafted AFS symlink or mountpoint to cause a denial of service.

The issue occurs because AS_RELEASE_ALWAYS is set for AFS symlinks and mountpoints even though their address space operations do not provide a release_folio callback.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/81e985b4c3a6cbcc443fcdcd3ebda7fcc845d459
• https://git.kernel.org/stable/c/9d6b0f6d437e2f8350e08678e5e1d20c11c364f3