CVE-2026-68442 (GCVE-0-2026-68442)
Vulnerability from cvelistv5
Published
2026-08-12 00:07
Modified
2026-10-19 21:09
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: don't propagate EXTENT_FLAG_LOGGING to split extent maps When btrfs_drop_extent_map_range() splits an extent map, the new split maps inherit the original map's flags through a local 'flags' variable. Commit f86f7a75e2fb ("btrfs: use the flags of an extent map to identify the compression type") changed the EXTENT_FLAG_LOGGING clearing to operate on em->flags instead of that local 'flags' copy, so a split of an extent map that is currently being logged wrongly inherits EXTENT_FLAG_LOGGING. The flag is then never cleared on the split, and when it is freed while still on the inode's modified_extents list (for example by the extent map shrinker) it trips the WARN_ON(!list_empty(&em->list)) in btrfs_free_extent_map() and leads to a use-after-free. Clear EXTENT_FLAG_LOGGING from the local 'flags' copy used for the splits and only clear EXTENT_FLAG_PINNED from em->flags, restoring the behaviour prior to f86f7a75e2fb.
References
Impacted products
Vendor Product Version
Linux Linux Version: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9
Version: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9
Version: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9
Version: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9
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