CVE-2026-74566 keys: make keyring key-chunk byte order agree with keyring_diff_objects()
A local attacker can craft key descriptions to cause collisions in the Linux kernel keyring, leading to a 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-2026-74566?
CVE-2026-74566 is a denial of service 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:
keys: make keyring key-chunk byte order agree with keyring_diff_objects()
keyring_get_key_chunk() loads description bytes into the index chunk low address first, while keyring_diff_objects() numbers the first differing bit from the low end and folds the absolute byte index into the level without removing the inline-prefix offset the level already carries. The two disagree on byte order and bit position, so the array can be told two keys first differ at a bit that does not differ in the chunk the walker uses, letting crafted descriptions collide into one node.
Load the chunk in the order keyring_diff_objects() assumes and drop the inline-prefix length when folding the byte index into the level. This only changes the in-memory ordering used to place keys within a keyring; add, search and read of non-colliding keys are unaffected.
Which versions are affected by CVE-2026-74566?
How do I fix CVE-2026-74566?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-74566 being exploited?
There is no known exploitation of CVE-2026-74566 in the wild and no public exploit code.
Sources
Also known as AZL-96093, BELL-CVE-2026-74566, DEBIAN-CVE-2026-74566, GHSA-987h-mx48-c6mp, UBUNTU-CVE-2026-74566.