CVE-2026-43117
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Btrfs Sync File Use-After-Free via OverlayFS

Publication date: 2026-05-06

Last updated on: 2026-06-01

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file() If overlay is used on top of btrfs, dentry->d_sb translates to overlay's super block and fsid assignment will lead to a crash. Use file_inode(file)->i_sb to always get btrfs_sb.
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Meta Information
Published
2026-05-06
Last Modified
2026-06-01
Generated
2026-06-16
AI Q&A
2026-05-06
EPSS Evaluated
2026-06-15
NVD
CVE-2026-43117
EUVD
EUVD-2026-27643
Affected Vendors & Products
Showing 9 associated CPEs
Vendor Product Version / Range
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel From 6.13 (inc) to 6.18.24 (exc)
linux linux_kernel From 6.19 (inc) to 6.19.14 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.83 (exc)
linux linux_kernel From 4.8 (inc) to 6.6.136 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's btrfs filesystem tracepoints. Specifically, when an overlay filesystem is used on top of btrfs, the code incorrectly retrieves the superblock from a dentry structure. Instead of getting the btrfs superblock, it gets the overlay's superblock, which causes incorrect fsid assignment and can lead to a system crash.

The fix involves changing the code to use file_inode(file)->i_sb to always get the correct btrfs superblock.

Impact Analysis

This vulnerability can cause a system crash when using an overlay filesystem on top of btrfs due to incorrect superblock handling. Such crashes can lead to system instability, potential data loss, and downtime.

Mitigation Strategies

The vulnerability has been resolved by correcting the way the superblock is retrieved in the btrfs tracepoints, specifically by using file_inode(file)->i_sb to always get the correct btrfs superblock.

To mitigate this vulnerability, you should update your Linux kernel to a version that includes this fix.

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