CVE-2025-21983

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2025-04-01. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq

Currently kvfree_rcu() APIs use a system workqueue which is "system_unbound_wq" to driver RCU machinery to reclaim a memory.

Recently, it has been noted that the following kernel warning can be observed:

workqueue: WQ_MEM_RECLAIM nvme-wq:nvme_scan_work is flushing !WQ_MEM_RECLAIM events_unbound:kfree_rcu_work WARNING: CPU: 21 PID: 330 at kernel/workqueue.c:3719 check_flush_dependency+0x112/0x120 Modules linked in: intel_uncore_frequency(E) intel_uncore_frequency_common(E) skx_edac(E) ... CPU: 21 UID: 0 PID: 330 Comm: kworker/u144:6 Tainted: G E 6.13.2-0_g925d379822da #1 Hardware name: Wiwynn Twin Lakes MP/Twin Lakes Passive MP, BIOS YMM20 02/01/2023 Workqueue: nvme-wq nvme_scan_work RIP: 0010:check_flush_dependency+0x112/0x120 Code: 05 9a 40 14 02 01 48 81 c6 c0 00 00 00 48 8b 50 18 48 81 c7 c0 00 00 00 48 89 f9 48 ... RSP: 0018:ffffc90000df7bd8 EFLAGS: 00010082 RAX: 000000000000006a RBX: ffffffff81622390 RCX: 0000000000000027 RDX: 00000000fffeffff RSI: 000000000057ffa8 RDI: ffff88907f960c88 RBP: 0000000000000000 R08: ffffffff83068e50 R09: 000000000002fffd R10: 0000000000000004 R11: 0000000000000000 R12: ffff8881001a4400 R13: 0000000000000000 R14: ffff88907f420fb8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88907f940000(0000) knlGS:0000000000000000 CR2: 00007f60c3001000 CR3: 000000107d010005 CR4: 00000000007726f0 PKRU: 55555554 Call Trace: ? __warn+0xa4/0x140 ? check_flush_dependency+0x112/0x120 ? report_bug+0xe1/0x140 ? check_flush_dependency+0x112/0x120 ? handle_bug+0x5e/0x90 ? exc_invalid_op+0x16/0x40 ? asm_exc_invalid_op+0x16/0x20 ? timer_recalc_next_expiry+0x190/0x190 ? check_flush_dependency+0x112/0x120 ? check_flush_dependency+0x112/0x120 __flush_work.llvm.1643880146586177030+0x174/0x2c0 flush_rcu_work+0x28/0x30 kvfree_rcu_barrier+0x12f/0x160 kmem_cache_destroy+0x18/0x120 bioset_exit+0x10c/0x150 disk_release.llvm.6740012984264378178+0x61/0xd0 device_release+0x4f/0x90 kobject_put+0x95/0x180 nvme_put_ns+0x23/0xc0 nvme_remove_invalid_namespaces+0xb3/0xd0 nvme_scan_work+0x342/0x490 process_scheduled_works+0x1a2/0x370 worker_thread+0x2ff/0x390 ? pwq_release_workfn+0x1e0/0x1e0 kthread+0xb1/0xe0 ? __kthread_parkme+0x70/0x70 ret_from_fork+0x30/0x40 ? __kthread_parkme+0x70/0x70 ret_from_fork_asm+0x11/0x20 ---[ end trace 0000000000000000 ]---

To address this switch to use of independent WQ_MEM_RECLAIM workqueue, so the rules are not violated from workqueue framework point of view.

Apart of that, since kvfree_rcu() does reclaim memory it is worth to go with WQ_MEM_RECLAIM type of wq because it is designed for this purpose.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

April 1, 2025

Last Modified

October 30, 2025

References (3)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.12.20—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Data Freshness Timeline

(refreshed 7× in last 7d / 38× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 106 total refreshes for this CVE.

  1. 2026-08-07 16:26 UTCEPSS rescore
  2. 2026-08-06 13:46 UTCEPSS rescore
  3. 2026-08-05 19:16 UTCEPSS rescore
  4. 2026-08-04 15:09 UTCEPSS rescore
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  15. 2026-07-24 10:41 UTCOSV refresh
  16. 2026-07-23 14:17 UTCEPSS rescore
  17. 2026-07-23 02:50 UTCEG score recompute
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  25. 2026-07-18 10:03 UTCEPSS rescore
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  1. 2026-07-16 17:02 UTCEPSS rescore
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  9. 2026-07-12 05:46 UTCEPSS rescore
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  11. 2026-07-11 08:27 UTCEPSS rescore
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  13. 2026-07-09 19:09 UTCEPSS rescore
  14. 2026-07-08 15:14 UTCEPSS rescore
  15. 2026-07-07 13:45 UTCEPSS rescore
  16. 2026-07-07 05:51 UTCOSV refresh
  17. 2026-07-06 16:26 UTCEPSS rescore
  18. 2026-07-06 02:22 UTCEPSS rescore
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  20. 2026-07-05 02:30 UTCEPSS rescore
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  22. 2026-07-01 15:06 UTCEPSS rescore
  23. 2026-06-30 23:21 UTCEPSS rescore
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  25. 2026-06-29 14:06 UTCEPSS rescore
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  28. 2026-06-28 04:55 UTCEPSS rescore
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  30. 2026-06-27 03:08 UTCEPSS rescore
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  40. 2026-06-21 14:56 UTCEPSS rescore
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  42. 2026-06-21 01:59 UTCEPSS rescore
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  44. 2026-06-19 19:25 UTCEPSS rescore
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  46. 2026-06-18 17:52 UTCEPSS rescore
  47. 2026-06-18 17:52 UTCEPSS rescore
  48. 2026-06-18 17:05 UTCOSV refresh
  49. 2026-06-16 17:52 UTCEPSS rescore
  50. 2026-06-16 17:52 UTCEPSS rescore
  51. 2026-06-15 17:48 UTCEPSS rescore
  52. 2026-06-14 23:17 UTCEPSS rescore
  53. 2026-06-13 22:59 UTCEPSS rescore
  54. 2026-06-12 23:11 UTCEPSS rescore
  55. 2026-06-11 13:59 UTCEPSS rescore
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  62. 2026-06-06 13:47 UTCEPSS rescore
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  72. 2026-06-01 13:51 UTCEPSS rescore
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  74. 2026-05-31 22:30 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2025-21983?
CVE-2025-21983 is a high vulnerability published on April 1, 2025. In the Linux kernel, the following vulnerability has been resolved: mm/slab/kvfreercu: Switch to WQMEM_RECLAIM wq Currently kvfree_rcu() APIs use a system workqueue which is "systemunboundwq" to driver RCU machinery to reclaim a memory. Recently, it has been noted that the following kernel warning…
When was CVE-2025-21983 disclosed?
CVE-2025-21983 was first published in the National Vulnerability Database on April 1, 2025, with the most recent update on October 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21983 actively exploited?
CVE-2025-21983 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 91.5% of all scored CVEs.
What is the CVSS score of CVE-2025-21983?
CVE-2025-21983 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2025-21983?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21983, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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