Is CVE-2025-21795 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 0%.

What products does CVE-2025-21795 affect?

Tracked products affected include Linux Kernel. Check the version you run to see whether it is affected.

How do I fix CVE-2025-21795?

Apply the vendor fix promptly. An official patch or advisory is available. Upgrade affected products to a fixed version.

← All products

CVE-2025-21795

Q: What is CVE-2025-21795?

CVE-2025-21795 is a high-severity software vulnerability with a CVSS score of 7.5. In the Linux kernel, the following vulnerability has been resolved: NFSD: fix hang in nfsd4_shutdown_callback If nfs4_client is in courtesy state then there is no point to send the callback. This causes nfsd4_shutdown_callback to hang sin

HIGH severity · CVSS 7.5

7.5CVSS HIGH

Summary

In the Linux kernel, the following vulnerability has been resolved: NFSD: fix hang in nfsd4_shutdown_callback If nfs4_client is in courtesy state then there is no point to send the callback. This causes nfsd4_shutdown_callback to hang since cl_cb_inflight is not 0. This hang lasts about 15 minutes until TCP notifies NFSD that the connection was dropped. This patch modifies nfsd4_run_cb_work to skip the RPC call if nfs4_client is in courtesy state.

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

Confidentiality impactNone

Integrity impactNone

Availability impactHigh

Exploit probability (EPSS)0%

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products we track (1)

Linux Kernel

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/036ac2778f7b28885814c6fbc07e156ad1624d03 ↗

CVE-2025-21795

Summary

Impact & exploitability

Affected products we track (1)

Recommendation

Additional information