CVE-2026-93106 crash_dump: release keyring reference at the correct time
A use-after-free vulnerability in the Linux kernel's crash_dump module allows local attackers with high privileges to cause a system crash or potentially escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93106?
CVE-2026-93106 is an use after free vulnerability in Linux, published on 17 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:
crash_dump: release keyring reference at the correct time
restore_dm_crypt_keys_to_thread_keyring() gets a reference to the user keyring before restoring the saved dm-crypt keys.
The same keyring reference is then passed to add_key_to_keyring() for each saved key, but add_key_to_keyring() drops that reference on every call. This is only balanced when exactly one key is restored. With multiple keys, the keyring reference is dropped too many times and may trigger a refcount underflow or use-after-free.
When more than five keys are restored, a refcount underflow/use-after-free warning can be triggered.
The early error paths after lookup_user_key() also return without dropping the keyring reference.
Keep ownership of the keyring reference in restore_dm_crypt_keys_to_thread_keyring(), drop it once on all exit paths, and make add_key_to_keyring() only use the reference without consuming it.
Which versions are affected by CVE-2026-93106?
How do I fix CVE-2026-93106?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-93106 being exploited?
There is no known exploitation of CVE-2026-93106 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93106, DEBIAN-CVE-2026-93106, GHSA-ggxj-6q52-m3ww, UBUNTU-CVE-2026-93106.