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Summary
vulnerability in linux (CVE-2026-43067). Successful exploitation can lead to full system takeover.
AI summary openai / gpt-4o
This issue in the Linux kernel can lead to improper block allocation in the ext4 filesystem, posing a risk to system-wide data integrity. Similar issues have been seen in other filesystems before, requiring immediate attention. Your company should promptly update systems to the latest version.
This vulnerability in Linux kernel's ext4 allows blocks to be potentially allocated beyond group limits. Although the specific affected versions are not outlined, the fix involves adding a safety clamp in the ext4_mb_scan_groups() function. Attackers can exploit this flaw without authentication to manipulate system data. It is recommended to apply the related kernel patches to mitigate this issue.
❓ What is the problem
This vulnerability allows improper block allocation beyond specified group limits in the Linux kernel's ext4 filesystem.
📍 Affected scope
In the function ext4_mb_scan_groups() within the Linux kernel.
🔥 Severity
Critical, as per CVSS score of 9.8, allowing remote attacks without need for authentication.
🔧 How to fix
Apply the kernel patch that adds a safety clamp in ext4_mb_scan_groups().
🛡️ Workaround
No specific workaround provided.
🔍 Detection
Detect if ext4_mb_scan_groups() function is handling unexpected group limits in ext4 files.
Related past incidents Similar incidents extracted from past CVEs
An issue in the ext4 file system that allowed reading beyond a buffer boundary.
An ext4-related security vulnerability that allowed local users to corrupt file system.
An ext4 file system vulnerability related to improper block allocation.
If this happens at your company Expected impact per business scenario
📌 For cloud providers using OpenStack with ext4 file systems.
Tenants might experience data corruption or loss, affecting service availability.
📌 On enterprise servers using ext4 on Linux.
Could result in unauthorized block access, leading to potential data breaches.
📌 For companies running ext4 on critical systems.
Possible system-wide data corruption causing operational disruptions.
Recommended action
Apply updates to the Linux kernel to mitigate this risk as soon as a patch is available.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.依存マニフェストで影響コンポーネントを特定する。
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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
- web https://git.kernel.org/stable/c/12624c5b724a81e14e532972b40d863b0de3b7d1
- web https://git.kernel.org/stable/c/2a368ccddfc492a0aa951e2caef2985f20e96503
- web https://git.kernel.org/stable/c/4bec4a498ce86314d470ae6144120461f2138c29
- web https://git.kernel.org/stable/c/83170a05908b6cf2fb3235d3065bf613ff866f3c
- web https://git.kernel.org/stable/c/bb81702370fad22c06ca12b6e1648754dbc37e0f
- web https://git.kernel.org/stable/c/f89bba144938921a2249237ad04a0183ff3f8930
- web https://nvd.nist.gov/vuln/detail/CVE-2026-43067
- web https://github.com/advisories/GHSA-845x-q62g-4v8p