CVE-2026-74343
Received Received - Intake

BaseFortify

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description
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

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Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
CVE-2026-74343
EUVD
EUVD-2026-59490

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in xattr operations due to multiple superblocks sharing the same kernfs_node. The issue occurs because the VFS layer's per-inode locks are insufficient to prevent concurrent modifications from different superblocks, leading to potential data corruption or unexpected behavior.

Detection Guidance

This vulnerability is specific to the Linux kernel and involves race conditions in xattr operations. Detection typically requires kernel-level monitoring or auditing tools. Check for kernel logs or errors related to xattr operations or kernfs_node issues. Use commands like dmesg | grep -i xattr or journalctl -k | grep -i xattr to inspect kernel logs for suspicious activity.

Impact Analysis

If exploited, this vulnerability could allow attackers to manipulate extended attributes (xattrs) in a way that causes race conditions, potentially leading to data corruption, privilege escalation, or denial of service on affected Linux systems.

Mitigation Strategies

Apply the latest kernel patches or updates that include the fix for this vulnerability. Monitor kernel security advisories and update your system to a patched kernel version. If immediate patching is not possible, consider isolating affected systems or restricting access to reduce exposure.

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