CVE-2025-39697 NFS: Fix a race when updating an existing write

What is CVE-2025-39697?

CVE-2025-39697 is a high-severity vulnerability in Debian Debian Linux, published on 5 Sep 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:

NFS: Fix a race when updating an existing write

After nfs_lock_and_join_requests() tests for whether the request is still attached to the mapping, nothing prevents a call to nfs_inode_remove_request() from succeeding until we actually lock the page group. The reason is that whoever called nfs_inode_remove_request() doesn't necessarily have a lock on the page group head.

So in order to avoid races, let's take the page group lock earlier in nfs_lock_and_join_requests(), and hold it across the removal of the request in nfs_inode_remove_request().

Weakness: CWE-362

Which versions are affected by CVE-2025-39697?

It affects 2 products.

Products include Debian Debian Linux, Linux kernel.

How do I fix CVE-2025-39697?

Apply the vendor's patch.

Is CVE-2025-39697 being exploited?

There is no known exploitation of CVE-2025-39697 in the wild and no public exploit code.

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All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-66926, AZL-73716, BELL-CVE-2025-39697, DEBIAN-CVE-2025-39697, GHSA-3fr6-pgc4-qmrv, ROOT-OS-DEBIAN-11-CVE-2025-39697 and 5 more.