CVE-2025-21893
CVE vulnerability detail — eXtreme Datacenter Security Operations
Description
In the Linux kernel, the following vulnerability has been resolved: keys: Fix UAF in key_put() Once a keys reference count has been reduced to 0, the garbage collector thread may destroy it at any time and so key_put() is not allowed to touch the key after that point. The most key_put() is normally allowed to do is to touch key_gc_work as thats a static global variable. However, in an effort to speed up the reclamation of quota, this is now done in key_put() once the keys usage is reduced to 0 - but now the code is looking at the key after the deadline, which is forbidden. Fix this by using a flag to indicate that a key can be gcd now rather than looking at the keys refcount in the garbage collector.