Vulnerability in Kernel (CVE-2025-21983)

Summary

Vulnerability in Kernel (CVE-2025-21983). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.12.20, 6.13.8 or later.

Original description

The description as published by the source.

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: 000…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2025-21983 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.12.20, 6.13.8 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-21983" on the vendor's site.

CVE-2025-21983 (Kernel)
Patched: 6.12.20, 6.13.8 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 6.12.20, 6.13.8.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Kernel' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'Kernel' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Kernel を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade Kernel to 6.12.20, 6.13.8
```
ステージング環境で 6.12.20, 6.13.8 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.12.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.13.8"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21983 linux-lts Fixed in: 6.12.41-r0
Debian DEBIAN-CVE-2025-21983 linux Fixed in: 6.12.20-1