In the Linux kernel, the following vulnerability has been resolved: virtiofs: fix UAF on submount umount iput() called from fuse_release_end() can… (CVE-2026-53381)
A use-after-free (UAF) vulnerability in the Linux kernel's virtiofs component related to submount unmounting has been resolved. The issue occurs because iput() called from fuse_release_end() can cause a kernel Oops if the superblock has already been destroyed. This happens due to improper synchronization when multiple submount instances exist, as the wait counter is per connection rather than per superblock. The fix involves reverting to synchronous release requests for the auto_submounts case, currently specific to virtiofs.
AI Analysis
Technical Summary
The vulnerability in the Linux kernel's virtiofs subsystem involves a use-after-free condition triggered during submount unmount operations. Specifically, iput() invoked from fuse_release_end() can cause a kernel Oops if the superblock has been destroyed prematurely. The root cause is that the synchronization mechanism relies on a wait counter per connection, which does not adequately protect the superblock when multiple submount instances exist. The resolution reverts to synchronous release requests for auto_submounts to ensure proper synchronization and prevent the use-after-free scenario.
Potential Impact
This vulnerability can lead to a kernel Oops (crash) due to use-after-free of the superblock structure during submount unmount operations in virtiofs. This may cause denial of service or instability in systems using virtiofs with submounts. No information about privilege escalation or data corruption is provided.
Mitigation Recommendations
A fix has been implemented that reverts to synchronous release requests for the auto_submounts case in virtiofs, preventing the use-after-free condition. Users should apply the official Linux kernel updates that include this fix once available. Patch status is not yet confirmed in the provided data; check the vendor advisory or Linux kernel mailing lists for the current remediation guidance.
In the Linux kernel, the following vulnerability has been resolved: virtiofs: fix UAF on submount umount iput() called from fuse_release_end() can… (CVE-2026-53381)
Description
A use-after-free (UAF) vulnerability in the Linux kernel's virtiofs component related to submount unmounting has been resolved. The issue occurs because iput() called from fuse_release_end() can cause a kernel Oops if the superblock has already been destroyed. This happens due to improper synchronization when multiple submount instances exist, as the wait counter is per connection rather than per superblock. The fix involves reverting to synchronous release requests for the auto_submounts case, currently specific to virtiofs.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in the Linux kernel's virtiofs subsystem involves a use-after-free condition triggered during submount unmount operations. Specifically, iput() invoked from fuse_release_end() can cause a kernel Oops if the superblock has been destroyed prematurely. The root cause is that the synchronization mechanism relies on a wait counter per connection, which does not adequately protect the superblock when multiple submount instances exist. The resolution reverts to synchronous release requests for auto_submounts to ensure proper synchronization and prevent the use-after-free scenario.
Potential Impact
This vulnerability can lead to a kernel Oops (crash) due to use-after-free of the superblock structure during submount unmount operations in virtiofs. This may cause denial of service or instability in systems using virtiofs with submounts. No information about privilege escalation or data corruption is provided.
Mitigation Recommendations
A fix has been implemented that reverts to synchronous release requests for the auto_submounts case in virtiofs, preventing the use-after-free condition. Users should apply the official Linux kernel updates that include this fix once available. Patch status is not yet confirmed in the provided data; check the vendor advisory or Linux kernel mailing lists for the current remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-525m-f6h4-6w58
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-53381"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a5d27ad2a4a8d59891325ab
Added to database: 07/19/2026, 19:38:21 UTC
Last enriched: 07/19/2026, 20:24:32 UTC
Last updated: 07/20/2026, 17:26:47 UTC
Views: 14
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