CVE-2026-93106 in Linux
Zusammenfassung
von MITRE • 18.09.2026
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.
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