CVE-2025-21900: NFSv4: Fix a deadlock when recovering state on a sillyrenamed file
In the Linux kernel, the following vulnerability has been resolved:
NFSv4: Fix a deadlock when recovering state on a sillyrenamed file
If the file is sillyrenamed, and slated for delete on close, it is possible for a server reboot to triggeer an open reclaim, with can again race with the application call to close(). When that happens, the call to putnfsopencontext() can trigger a synchronous delegreturn call which deadlocks because it is not marked as privileged.
Instead, ensure that the call to nfs4inodereturndelegationonclose() catches the delegreturn, and schedules it asynchronously.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21900?
CVE-2025-21900 has a high severity rating due to the potential for system deadlocks affecting server recovery operations.
How do I fix CVE-2025-21900?
To fix CVE-2025-21900, update your Linux kernel to versions 6.12.18, 6.13.6, or later as these releases contain the necessary patches.
Which versions of the Linux kernel are affected by CVE-2025-21900?
CVE-2025-21900 affects Linux kernel versions from 6.11 up to 6.14-rc4, specifically the versions outlined between those ranges.
What type of system is impacted by CVE-2025-21900?
CVE-2025-21900 impacts systems running the Linux kernel, particularly those utilizing NFSv4 with sillyrenamed files.
Is there a known exploit for CVE-2025-21900?
As of now, there are no publicly known exploits specifically targeting CVE-2025-21900, but its vulnerability could be leveraged in certain scenarios.