Out-of-Bounds Write in linux (CVE-2026-43125, CVSS 9.8)

Summary

out-of-bounds write in linux (CVE-2026-43125). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

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

dlm: validate length in dlm_search_rsb_tree

The len parameter in dlm_dump_rsb_name() is not validated and comes
from network messages. When it exceeds DLM_RESNAME_MAXLEN, it can
cause out-of-bounds write in dlm_search_rsb_tree().

Add length validation to prevent potential buffer overflow.

Source: NIST National Vulnerability Database NVD GitHub Advisory

AI summary

Written by an external AI model and may contain mistakes. Check the original description and references below before acting on it.

A vulnerability tracked as CVE-2026-43125 has been found in linux.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "linux CVE-2026-43125" on the vendor's site.

CVE-2026-43125 (linux) — CWE-787 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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

out-of-bounds write (CWE-787) exists in linux.

📍 Affected scope

linux — .

🔥 Severity

Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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.

Related past incidents Similar incidents extracted from past CVEs

CVE-2021-3156

一般的なLinuxシステムでのバッファオーバーフローでのroot乗っ取りが可能

Heartbleed

ネットワークを経由してメモリを覗き見するOpenSSLの致命的な脆弱性

CVE-2022-0185

Linuxカーネルのexploitが公開され、root権限でのコード実行を許す

If this happens at your company Expected impact per business scenario

📌 クラウドベースのLinux仮想マシン

攻撃者が権限を取得し、顧客データの漏洩やシステム停止を引き起こす可能性があります。

📌 企業内のLinuxサーバー

重要な業務データの改ざんや、システムの不正使用につながるリスクがあります。

📌 IoTデバイスに組み込まれたLinuxカーネル

デバイスが乗っ取られ、大規模なDDoS攻撃の一部として悪用される可能性があります。

Recommended action

全Linuxシステムで速やかにパッチを適用し、継続的なセキュリティ監視を実施する。

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。
7
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 Step 3 と同じログクエリでアラート再発が無いか継続監視。

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-43125 linux-lts
Debian DEBIAN-CVE-2026-43125 linux
Ubuntu UBUNTU-CVE-2026-43125 linux

Out-of-Bounds Write in linux (CVE-2026-43125)