CVE-2023-53672: btrfs: output extra debug info if we failed to find an inline backref

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-07 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: output extra debug info if we failed to find an inline backref [BUG] Syzbot reported several warning triggered inside lookup_inline_extent_backref(). [CAUSE] As usual, the reproducer doesn't reliably trigger locally here, but at least we know the WARN_ON() is triggered when an inline backref can not be found, and it can only be triggered when @insert is true. (I.e. inserting a new inline backref, which means the backref should already exist) [ENHANCEMENT] After the WARN_ON(), dump all the parameters and the extent tree leaf to help debug.

Affected products

Linux kernel: from 3.9.1 before 4.14.326; from 4.15 before 4.19.295; from 4.20 before 5.4.257; from 5.5 before 5.10.197; from 5.11 before 5.15.133; from 5.16 before 6.1.55 — fixed in 4.14.326, 4.19.295, 5.10.197, 5.15.133, 5.4.257, 6.1.55

How to fix

Upgrade to a fixed version: Linux kernel 4.14.326, 4.19.295, 5.10.197, 5.15.133. Check the vendor advisory for mitigations.

References

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