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CVE-2026-43038
critical
CVSS 9.8
Vulnerability in linux (CVE-2026-43038)
Summary
vulnerability in linux (CVE-2026-43038). Successful exploitation can lead to full system takeover.
AI summary openai / gpt-4o
This vulnerability allows malicious attackers to remotely access systems through the internet and take control over the network. Specifically, attackers could harm the system using forged ICMP messages. Similar issues in the past have caused entire networks to go down. It is highly recommended for organizations to update their systems to the latest version.
The vulnerability involves the handling of IPv4 ICMP error packets in the ip6_err_gen_icmpv6_unreach() function. If an attacker sends a forged ICMPv4 error packet with a CIPSO option, an incorrect non-zero offset may be recognized in icmp6_send(), leading to operations extending beyond packet data bounds. This issue has been patched in the Linux Kernel.
❓ What is the problem
Critical vulnerability in Linux kernel concerning handling of IPv4 ICMP error packets.
📍 Affected scope
In the ip6_err_gen_icmpv6_unreach() function of Linux Kernel's ICMP processing.
🔥 Severity
Critical, with CVSS v3 score of 9.8, allowing remote attacks without authentication.
🔧 How to fix
Update to the latest patched version of the Linux Kernel.
🛡️ Workaround
No specific workaround; recommended to apply the patch.
🔍 Detection
Use network monitoring tools to track unusual ICMPv4 and ICMPv6 traffic.
Related past incidents Similar incidents extracted from past CVEs
Similar issue in ICMPv6 affecting Linux kernel leading to memory corruption.
Vulnerability related to ICMP errors and IPv6 in Linux Kernel.
Bluetooth vulnerability in Linux kernel similar in its remote exploitation nature.
If this happens at your company Expected impact per business scenario
📌 ECサイトのサービス運用
ネットワークを経由してサーバーを不正に操作され、取引の信頼性に影響が出る可能性がある。
📌 社内ネットワークのセキュリティ
外部からの不正アクセスで機密情報が漏洩するリスクが高まる。
📌 クラウドサービスの提供
サービスの継続性が脅かされ、顧客への影響が出る可能性が高い。
Recommended action
企業はシステムの最新バージョンへのアップデートを迅速に実施し、ネットワークトラフィックの監視を強化するべきです。
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify 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。
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7Post-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。
References
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- patch 416baaa9-dc9f-4396-8d5f-8c081fb06d67