CVE-2025-68239 binfmt_misc: restore write access before closing files opened by open_exec()
A local attacker with high privileges can cause write failures on executable files by triggering an error in binfmt_misc registration, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68239?
CVE-2025-68239 is a vulnerability in Linux, published on 16 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
binfmt_misc: restore write access before closing files opened by open_exec()
bm_register_write() opens an executable file using open_exec(), which internally calls do_open_execat() and denies write access on the file to avoid modification while it is being executed.
However, when an error occurs, bm_register_write() closes the file using filp_close() directly. This does not restore the write permission, which may cause subsequent write operations on the same file to fail.
Fix this by calling exe_file_allow_write_access() before filp_close() to restore the write permission properly.
Which versions are affected by CVE-2025-68239?
How do I fix CVE-2025-68239?
Apply the vendor's patch.
Is CVE-2025-68239 being exploited?
There is no known exploitation of CVE-2025-68239 in the wild and no public exploit code.
Sources
Also known as AZL-72499, BELL-CVE-2025-68239, DEBIAN-CVE-2025-68239, GHSA-6286-qq46-83p9, ROOT-OS-DEBIAN-11-CVE-2025-68239, ROOT-OS-DEBIAN-12-CVE-2025-68239 and 4 more.