Vulnerability in Kernel (CVE-2025-40083)

Summary

Vulnerability in Kernel (CVE-2025-40083). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.116, 6.12.57 or later.

Original description

The description as published by the source.

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

net/sched: sch_qfq: Fix null-deref in agg_dequeue

To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c)
when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return
value before using it, similar to the existing approach in sch_hfsc.c.

To avoid code duplication, the following changes are made:

Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static
inline function.
Moved qdisc_peek_len from net/sched/sch_hfsc.c to
include/net/pkt_sched.h so that sch_qfq can reuse it.
Applied qdisc_peek_len in agg_dequeue to avoid crashing.

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-2025-40083 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.116, 6.12.57 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-40083" on the vendor's site.

CVE-2025-40083 (Kernel)
Patched: 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.116, 6.12.57 — 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 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.116, 6.12.57.

🛡️ 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 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.116, 6.12.57
```
ステージング環境で 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.116, 6.12.57 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":"3.8.0"},{"fixed":"5.4.302"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.247"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.197"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.159"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.116"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.57"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-40083 linux-lts Fixed in: 6.1.159-r0
Debian DEBIAN-CVE-2025-40083 linux Fixed in: 5.10.247-1
Ubuntu UBUNTU-CVE-2025-40083 linux