CVE-2026-99226
In the Linux kernel, the following vulnerability has been resolved: keys: Avoid the owner account dereference in named keyring lookup Named keyring lookup must…
Impact
In the Linux kernel, the following vulnerability has been resolved: keys: Avoid the owner account dereference in named keyring lookup Named keyring lookup must keep the storage containing the owner UID alive through the namespace mapping check. find_keyring_by_name() reads keyring->user->uid under keyring_name_lock, but that lock protects the keyring's name entry and allocation, not its separate key_user. A named session-keyring join can overlap a privileged KEYCTL_CHOWN on another CPU. If the keyring holds the last reference to its old dynamic key_user and the ownership transfer succeeds, the following ordering is possible: Named join Chown find_keyring_by_name() keyctl_chown_key() read_lock(keyring_name_lock) down_write(key->sem) load old keyring->user replace key->user and key->uid up_write(key->sem) key_put(key) key_user_put(old user): free read old user->uid read_unlock(keyring_name_lock) Chown neither takes keyring_name_lock nor key_session_mutex, so it can free the old account between the pointer load and the UID read. The lookup then reads freed memory even though the keyring itself is alive. Use keyring->uid for the mapping check. key_alloc() initializes this inline owner UID and keyctl_chown_key() updates it on chown. The existing name lock keeps its containing keyring allocated throughout the check, so lookup no longer depends on the account's lifetime. This also matches the owner UID used by the permission check. KASAN report as below: BUG: KASAN: slab-use-after-free in find_keyring_by_name+0x577/0x5d0 Read of size 4 at addr ffff8881128ae2ec by task keycase/500
Affected products · Linux
| Product | Affected versions |
|---|---|
| Linux | from 2ea190d0a006ce5218baa6e798512652446a605a before 77249d4b1bb5ad43552b7023c4a0978937aa7a56 from 2ea190d0a006ce5218baa6e798512652446a605a before 0b865fa477d94ac96c26848aab1fd176397de3f6 from 2ea190d0a006ce5218baa6e798512652446a605a before 6763329f673d261641c79212abf773af77b2c922 from 2ea190d0a006ce5218baa6e798512652446a605a before aa03c8fb4334f14d218020f7431debf2b7766865 from 2ea190d0a006ce5218baa6e798512652446a605a before c9664f780f861dd9f11f120c7a03ed0993671ebb from 2ea190d0a006ce5218baa6e798512652446a605a before b0830a26e2c3008a6e21863126b4a0e68b2761cd |
References
- NVD record
- CVE.org record
- GitHub advisory
- https://git.kernel.org/stable/c/77249d4b1bb5ad43552b7023c4a0978937aa7a56
- https://git.kernel.org/stable/c/0b865fa477d94ac96c26848aab1fd176397de3f6
- https://git.kernel.org/stable/c/6763329f673d261641c79212abf773af77b2c922
- https://git.kernel.org/stable/c/aa03c8fb4334f14d218020f7431debf2b7766865
- https://git.kernel.org/stable/c/c9664f780f861dd9f11f120c7a03ed0993671ebb
- https://git.kernel.org/stable/c/b0830a26e2c3008a6e21863126b4a0e68b2761cd
- https://git.kernel.org/stable/c/5c6a9512887a6cc694d594d9c0b57c0841d215b5
- https://git.kernel.org/stable/c/40b12b93ae4ab9e22c3d571e9b09fd08afad53f6
- https://github.com/advisories/GHSA-9pjv-mg4c-3j9m
- https://nvd.nist.gov/vuln/detail/CVE-2026-99226
- https://git.kernel.org/stable/c/51409aaa01f8602552c336009fd22b226b0cdf1d