CVE-2025-38724 nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm()
A race condition in the Linux kernel NFS server allows attackers to trigger a use-after-free, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38724?
CVE-2025-38724 is a critical use after free vulnerability in Debian Debian Linux, published on 4 Sep 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:
nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm()
Lei Lu recently reported that nfsd4_setclientid_confirm() did not check the return value from get_client_locked(). a SETCLIENTID_CONFIRM could race with a confirmed client expiring and fail to get a reference. That could later lead to a UAF.
Fix this by getting a reference early in the case where there is an extant confirmed client. If that fails then treat it as if there were no confirmed client found at all.
In the case where the unconfirmed client is expiring, just fail and return the result from get_client_locked().
Weakness: CWE-416
Which versions are affected by CVE-2025-38724?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38724?
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-2025-38724 being exploited?
There is no known exploitation of CVE-2025-38724 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-66854, AZL-73839, BELL-CVE-2025-38724, DEBIAN-CVE-2025-38724, GHSA-x8r2-g34h-2v3j, ROOT-OS-DEBIAN-11-CVE-2025-38724 and 4 more.