Vulnerability in linux (DEBIAN-CVE-2026-31741)

Summary

Vulnerability in linux (DEBIAN-CVE-2026-31741). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.12.85-1 or later.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved: counter: rz-mtu3-cnt: prevent counter from being toggled multiple times Runtime PM counter is incremented / decremented each time the sysfs enable file is written to. If user writes 0 to the sysfs enable file multiple times, runtime PM usage count underflows, generating the following message. rz-mtu3-counter rz-mtu3-counter.0: Runtime PM usage count underflow! At the same time, hardware registers end up being accessed with clocks off in rz_mtu3_terminate_counter() to disable an already disabled channel. If user writes 1 to the sysfs enable file multiple times, runtime PM usage count will be incremented each time, requiring the same number of 0 writes to get it back to 0. If user writes 0 to the sysfs enable file while PWM is in progress, PWM is stopped without counter being the owner of the underlying MTU3 channel. Check against the cached count_is_enabled value and exit if the user is trying to set the same enable value.

Source: OSV.dev (Open Source Vulnerabilities) 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 DEBIAN-CVE-2026-31741 has been found in linux.
Risk of unauthorized operations or information disclosure.
What to do: upgrade linux to 6.12.85-1 or later.
If unsure, ask your IT team or search "linux DEBIAN-CVE-2026-31741" on the vendor's site.

DEBIAN-CVE-2026-31741 (linux)
Attack vector: local / no user interaction
Patched: 6.12.85-1 — 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 linux.

📍 Affected scope

Check the vendor advisory for the affected versions of linux.

🔥 Severity

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

🔧 How to fix

Update to 6.12.85-1.

🛡️ 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 'linux' . 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 'linux' . | 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 linux 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 linux to 6.12.85-1
```
ステージング環境で 6.12.85-1 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

Debian:13 linux

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.85-1"}]}]

Debian:14 linux

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.19.12-1"}]}]

References

advisory security-tracker.debian.org