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CVE-2026-74343 high CVSS 7.8

Vulnerability in Linux kernel (CVE-2026-74343)

Summary

Vulnerability in Linux kernel (CVE-2026-74343). 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:

kernfs: fix xattr race condition with multiple superblocks

Multiple superblocks with different namespaces can share the same
kernfs_node when kernfs_test_super() finds a matching root but
different namespace. This means multiple inodes from different
superblocks can reference the same kernfs_node->iattr->xattrs
structure.

The VFS layer only holds per-inode locks during xattr operations,
which is insufficient to serialize concurrent xattr modifications on
the shared kernfs_node. This can lead to race conditions in
simple_xattr_set() where the lookup->replace/remove sequence is not
atomic with respect to operations from other superblocks.

Fix this by protecting xattr operations with the existing hashed
kernfs_locks->open_file_mutex[] array, which is already used to
protect per-node open file data. The hashed mutex array provides
scalable per-node serialization (scaled by CPU count, up to 1024 locks
on 32+ CPU systems) with zero memory overhead.

Changes:

  • Rename open_file_mutex[] to node_mutex[] to reflect dual purpose
  • Add kernfs_node_lock_ptr() and kernfs_node_lock() helpers
  • Protect simple_xattr_set() calls in kernfs_xattr_set() and
    kernfs_vfs_user_xattr_set() with the hashed mutex
  • Update file.c to use new helpers via compatibility wrappers
  • Update documentation to explain the extended lock usage

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2026-74343 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-74343" on the vendor's site.

CVE-2026-74343 (Linux kernel) — CVSS v3 7.8
Attack vector: local / 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

A vulnerability (unclassified) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.8/10). 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. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    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":"7.1.0"},{"fixed":"7.1.5"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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