CVE-2026-43066 ext4: fix iloc.bh leak in ext4_fc_replay_inode() error paths
A memory leak in the Linux kernel ext4 filesystem can lead to resource exhaustion and denial of service during fast commit replay.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43066?
CVE-2026-43066 is a medium-severity memory corruption vulnerability in Linux kernel, published on 5 May 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:
ext4: fix iloc.bh leak in ext4_fc_replay_inode() error paths
During code review, Joseph found that ext4_fc_replay_inode() calls ext4_get_fc_inode_loc() to get the inode location, which holds a reference to iloc.bh that must be released via brelse().
However, several error paths jump to the 'out' label without releasing iloc.bh:
- ext4_handle_dirty_metadata() failure - sync_dirty_buffer() failure - ext4_mark_inode_used() failure - ext4_iget() failure
Fix this by introducing an 'out_brelse' label placed just before the existing 'out' label to ensure iloc.bh is always released.
Additionally, make ext4_fc_replay_inode() propagate errors properly instead of always returning 0.
Weakness: CWE-401
Which versions are affected by CVE-2026-43066?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43066?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-43066 being exploited?
There is no known exploitation of CVE-2026-43066 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43066, DEBIAN-CVE-2026-43066, GHSA-vqp8-9648-3qfh, ROOT-OS-DEBIAN-11-CVE-2026-43066, ROOT-OS-UBUNTU-2204-CVE-2026-43066, ROOT-OS-UBUNTU-2404-CVE-2026-43066 and 1 more.