CVE-2026-22980nfsd: provide locking for v4_end_grace
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No exploitation reported and no EPSS estimate yet.
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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
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before ca97360860eb02e3ae4ba42c19b439a0fcecbf06; from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before e8bfa2401d4c51eca6e48e9b33c798828ca9df61; from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before 34eb22836e0cdba093baac66599d68c4cd245a9d; from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before 06600719d0f7a723811c45e4d51f5b742f345309; from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before ba4811c8b433bfa681729ca42cc62b6034f223b0; from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before 53f07d095e7e680c5e4569a55a019f2c0348cdc6; from 7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6 before 2857bd59feb63fcf40fe4baf55401baea6b4feb4 | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 3.18 before 5.10.248; from 5.11 before 5.15.198; from 5.16 before 6.1.161; from 6.2 before 6.6.121; from 6.7 before 6.12.66; from 6.13 before 6.18.6; 6.19; 6.19; and 2 more ranges | NVD |
References
- https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06patch
- https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61patch
- https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9dpatch
- https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309patch
- https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0patch
- https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6patch
- https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.