CVE-2026-99136 dm-crypt: fix a tiny race condition in crypt_dec_pending
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-99136?
CVE-2026-99136 is a vulnerability in Linux, published on 28 Oct 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dm-crypt: fix a tiny race condition in crypt_dec_pending
crypt_dec_pending reads io->error before calling atomic_dec_and_test. Another context, for example crypt_endio called from an interrupt, may set io->error and drop its reference between the read and the decrement. crypt_dec_pending then drops the last reference and completes the bio with the stale status - so a read that failed and was never decrypted, or a write that failed, is reported as successful.
The read was placed before the decrement by commit b35f8caa0890 ("dm crypt: wait for endio to complete before destruction"), because that commit freed dm_crypt_io before calling bio_endio. This is no longer the case, dm_crypt_io lives in the per-bio data now.
Read io->error after atomic_dec_and_test instead. atomic_dec_and_test is fully ordered, so no additional barrier is needed.
Which versions are affected by CVE-2026-99136?
How do I fix CVE-2026-99136?
Upgrade to a fixed version.
Is CVE-2026-99136 being exploited?
There is no known exploitation of CVE-2026-99136 in the wild and no public exploit code.
Sources
Also known as AZL-111257, BELL-CVE-2026-99136, DEBIAN-CVE-2026-99136, GHSA-mgww-4g2j-r877, UBUNTU-CVE-2026-99136.