CVE-2022-49914: btrfs: fix inode list leak during backref walking at resolve_indirect_refs()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-01 · updated 2026-06-17
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix inode list leak during backref walking at resolve_indirect_refs() During backref walking, at resolve_indirect_refs(), if we get an error we jump to the 'out' label and call ulist_free() on the 'parents' ulist, which frees all the elements in the ulist - however that does not free any inode lists that may be attached to elements, through the 'aux' field of a ulist node, so we end up leaking lists if we have any attached to the unodes. Fix this by calling free_leaf_list() instead of ulist_free() when we exit from resolve_indirect_refs(). The static function free_leaf_list() is moved up for this to be possible and it's slightly simplified by removing unnecessary code.

Affected products

Linux kernel: from 3.5 before 4.14.299; from 4.15 before 4.19.265; from 4.20 before 5.4.224; from 5.5 before 5.10.154; from 5.11 before 5.15.78; from 5.16 before 6.0.8 — fixed in 4.14.299, 4.19.265, 5.10.154, 5.15.78, 5.4.224, 6.0.8

How to fix

Upgrade to a fixed version: Linux kernel 4.14.299, 4.19.265, 5.10.154, 5.15.78. Check the vendor advisory for mitigations.

References

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