CVE-2026-22980

HIGH EPSS 3.0%
Published Jan 23, 20265mo ago · Modified Jun 17, 20261w ago
7.8 CVSS 3.1
High
Find Similar
Published Jan 23, 2026 5mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: provide locking for v4_end_grace Writing to v4_end_grace can race with server shutdown and result in memory being accessed after it was freed - reclaim_str_hashtbl in particularly. We cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is held while client_tracking_op->init() is called and that can wait for an upcall to nfsdcltrack which can write to v4_end_grace, resulting in a deadlock. nfsd4_end_grace() is also called by the landromat work queue and this doesn't require locking as server shutdown will stop the work and wait for it before freeing anything that nfsd4_end_grace() might access. However, we must be sure that writing to v4_end_grace doesn't restart the work item after shutdown has already waited for it. For this we add a new flag protected with nn->client_lock. It is set only while it is safe to make client tracking calls, and v4_end_grace only schedules work while the flag is set with the spinlock held. So this patch adds a nfsd_net field "client_tracking_active" which is set as described. Another field "grace_end_forced", is set when v4_end_grace is written. After this is set, and providing client_tracking_active is set, the laundromat is scheduled. This "grace_end_forced" field bypasses other checks for whether the grace period has finished. This resolves a race which can result in use-after-free.

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
3.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-416 Use After Free Memory Safety

Affected Products 10

VendorProductVersionRange
linuxlinux_kernel*≥3.18  –  <5.10.248
linuxlinux_kernel*≥5.11  –  <5.15.198
linuxlinux_kernel*≥5.16  –  <6.1.161
linuxlinux_kernel*≥6.2  –  <6.6.121
linuxlinux_kernel*≥6.7  –  <6.12.66
linuxlinux_kernel*≥6.13  –  <6.18.6
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any

References 7

  • git.kernel.org https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61
    Patch