CVE-2026-99222

In the Linux kernel, the following vulnerability has been resolved:

keys: Protect the read method check against type removal

keyctl read key() checks key->type->read without holding key->sem. A reference keeps the key alive, but does not pin the module containing its type. A surviving RxRPC key can therefore be read while AF RXRPC is being unloaded:

KEYCTL READ task Module unload and key GC

lookup user key() permission / possession checks load key->type af rxrpc exit() unregister key type() GC: down write(key->sem) GC: retype to key type dead GC: up write(key->sem) unregister key type() returns free module() read saved type's read member

The final access can read freed module storage. The read invocation in keyctl read key() is already protected by key->sem, but the earlier method check is outside that critical section.

Move the method check into keyctl read key(), after key validate() and under its existing read hold on key->sem. The check and invocation then use the same protected type for length queries and every read retry. The GC cannot retype the key until the semaphore is released, and type unregistration waits for that GC pass before the module can be freed.

Return -EOPNOTSUPP when validation succeeds and the type has no read method. A temporary buffer may now be allocated before this result; allocation and copying to userspace remain outside the semaphore.