CVE-2026-99037 dm-crypt: reject the lmk IV mode with AEAD ciphers
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-99037?
CVE-2026-99037 is a vulnerability in Linux, published on 23 Oct 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dm-crypt: reject the lmk IV mode with AEAD ciphers
A "capi:" table line that pairs an AEAD cipher with the lmk IV mode, for example "capi:gcm(aes)-lmk" with the integrity:28:aead option, causes an oops when it is loaded. lmk sets tfms_count to 64, but crypt_alloc_tfms_aead only allocates one transform, so crypt_setkey reads past the end of the tfms_aead array and calls crypto_aead_setkey on the values it finds there.
lmk exists for compatibility with Loop-AES, which uses CBC, so refuse it with an AEAD cipher rather than allocate 64 AEAD transforms. The check cannot go in crypt_iv_lmk_ctr with the other lmk checks, because the IV constructor runs after crypt_set_key.
Note that this is not a security bug because the memory corruption can only be triggered by root.
Which versions are affected by CVE-2026-99037?
How do I fix CVE-2026-99037?
Upgrade to a fixed version.
Is CVE-2026-99037 being exploited?
There is no known exploitation of CVE-2026-99037 in the wild and no public exploit code.
Sources
Also known as AZL-110906, BELL-CVE-2026-99037, DEBIAN-CVE-2026-99037, GHSA-9xmg-p5vw-vprw, UBUNTU-CVE-2026-99037.