CVE-2026-72163 ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
A local attacker can trigger a kernel panic via direct I/O on unwritten extents in OCFS2, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72163?
CVE-2026-72163 is a vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
[BUG] A direct write over unwritten extents can panic the kernel in ocfs2_assure_trans_credits() when the journal aborts during DIO completion. The crash is a general protection fault from a NULL pointer dereference.
[CAUSE] ocfs2_dio_end_io_write() loops over a direct write's unwritten extents, marking each written under a single journal handle. If the journal aborts (for example after an I/O error) while the extent tree is being updated, the handle is left aborted with its transaction pointer cleared. The extent merge treats that failure as not critical and reports success, so the loop keeps using the handle. ocfs2_assure_trans_credits() reads the handle's remaining credits without first checking whether the handle is aborted, and that read dereferences the cleared transaction pointer.
[FIX] A journal abort is recorded in the handle itself, so callers are expected to test the handle rather than rely on a returned error. Make ocfs2_assure_trans_credits() do that, as the other ocfs2 journal helpers already do, and return -EROFS when the handle is aborted.
Which versions are affected by CVE-2026-72163?
How do I fix CVE-2026-72163?
Apply the vendor's patch.
Is CVE-2026-72163 being exploited?
There is no known exploitation of CVE-2026-72163 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72163, DEBIAN-CVE-2026-72163, GHSA-54g6-8m9x-g4c9, UBUNTU-CVE-2026-72163.