CVE-2025-21900

NFSv4: Fix a deadlock when recovering state on a sillyrenamed file

MEDIUM
5.5
CVSS Score
Published: April 1, 2025 at 03:26 PM UTC
Updated: August 5, 2026 at 12:44 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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 put_nfs_open_context() can trigger a synchronous delegreturn call which deadlocks because it is not marked as privileged. Instead, ensure that the call to nfs4_inode_return_delegation_on_close() catches the delegreturn, and schedules it asynchronously.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.11 ≤ v < 6.12.186.11 ≤ v < 6.13.66.11 ≤ v < 6.146.13 ≤ v < 6.13.66.14 rc16.14 rc26.14 rc36.14 rc4adb4b42d19aea91826621a8d0bac94cf2c08f8bc
Vendor states this is fixed in 4fe4ae6c2e01d028856b73b6328b12b8945df871 (fixed)
Vendor states this is fixed in 8f8df955f078e1a023ee55161935000a67651f38 (fixed)
Vendor states this is fixed in f41a60bc43e7abbc636fee78bed0d74c31e738b0 (fixed)
Vendor states this is fixed in 6.11 (unaffected)
Vendor states this is fixed in 6.12.18 (unaffected)
Vendor states this is fixed in 6.13.6 (unaffected)
Vendor states this is fixed in 6.14 (unaffected)

References (3)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4fe4ae6c2e01d028856b73b6328b12b8945df871
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/8f8df955f078e1a023ee55161935000a67651f38
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f41a60bc43e7abbc636fee78bed0d74c31e738b0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-667

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