CVE-2026-53381
Received Received - Intake

Use-After-Free in Linux Kernel virtiofs

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: virtiofs: fix UAF on submount umount iput() called from fuse_release_end() can Oops if the super block has already been destroyed. Normally this is prevented by waiting for num_waiting to go down to zero before commencing with super block shutdown. This only works, however, for the last submount instance, as the wait counter is per connection, not per superblock. Revert to using synchronous release requests for the auto_submounts case, which is virtiofs only at this time.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-53381
EUVD
EUVD-2026-45503

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 use-after-free (UAF) issue in the virtiofs filesystem. When a submount is unmounted, the fuse_release_end() function calls iput() which can cause a kernel crash if the super block has already been destroyed. The problem occurs because the wait counter for super block shutdown is per connection, not per super block, allowing the issue to persist for non-last submount instances. The fix reverts to using synchronous release requests for auto_submounts, which is specific to virtiofs.

Detection Guidance

This vulnerability is specific to the Linux kernel's virtiofs subsystem and may not have direct network detection methods. Check kernel logs for fuse-related errors or crashes using commands like dmesg | grep -i fuse or journalctl -k | grep -i fuse.

Impact Analysis

This vulnerability could lead to system crashes or instability if exploited. Users running systems with virtiofs, particularly those using virtualization with shared filesystems, may experience kernel oopses or unexpected shutdowns. It does not directly expose data but could disrupt services relying on virtiofs.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a Linux kernel issue related to a use-after-free (UAF) in the virtiofs subsystem. Compliance impacts would depend on system configuration and usage rather than the vulnerability itself.

Mitigation Strategies

Apply the latest Linux kernel updates to patch this issue. If using virtiofs, consider disabling auto_submounts if not required. Monitor kernel logs for fuse-related errors after applying updates.

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