CVE-2023-53867 ceph: fix potential use-after-free bug when trimming caps
A use-after-free vulnerability in the Linux kernel's Ceph filesystem allows attackers to cause a crash or potentially execute code via race conditions during cap trimming.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53867?
CVE-2023-53867 is a critical use after free vulnerability in Linux, published on 24 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ceph: fix potential use-after-free bug when trimming caps
When trimming the caps and just after the 'session->s_cap_lock' is released in ceph_iterate_session_caps() the cap maybe removed by another thread, and when using the stale cap memory in the callbacks it will trigger use-after-free crash.
We need to check the existence of the cap just after the 'ci->i_ceph_lock' being acquired. And do nothing if it's already removed.
Which versions are affected by CVE-2023-53867?
How do I fix CVE-2023-53867?
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-2023-53867 being exploited?
There is no known exploitation of CVE-2023-53867 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53867, DEBIAN-CVE-2023-53867, GHSA-f688-j3hq-jm53, ROOT-OS-DEBIAN-11-CVE-2023-53867, ROOT-OS-UBUNTU-2204-CVE-2023-53867, UBUNTU-CVE-2023-53867.