CVE-2026-93269 ext4: fix circular lock dependency in ext4_ext_migrate
A local attacker can trigger a deadlock in the ext4 filesystem during migration, causing a system denial of service.
- 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-2026-93269?
CVE-2026-93269 is a vulnerability in Linux, published on 24 Sep 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 circular lock dependency in ext4_ext_migrate
Move iput(tmp_inode) after ext4_writepages_up_write() to avoid a circular lock dependency between s_writepages_rwsem and sb_internal (freeze protection).
The deadlock scenario:
CPU0 (EXT4_IOC_MIGRATE) CPU1 (orphan cleanup during mount) ---- ---- ext4_ext_migrate() ext4_writepages_down_write() s_writepages_rwsem (write) ext4_evict_inode() sb_start_intwrite() [sb_internal] ... ext4_writepages() s_writepages_rwsem (read) [BLOCKED] iput(tmp_inode) ext4_evict_inode() sb_start_intwrite() [BLOCKED]
The tmp_inode is a temporary inode with nlink=0 created solely for building the extent tree. Its eviction does not require s_writepages_rwsem protection, so deferring iput() until after releasing the rwsem is safe.
Which versions are affected by CVE-2026-93269?
How do I fix CVE-2026-93269?
Apply the vendor's patch.
Is CVE-2026-93269 being exploited?
There is no known exploitation of CVE-2026-93269 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93269, DEBIAN-CVE-2026-93269, GHSA-9p82-h2x3-6rrv, UBUNTU-CVE-2026-93269.