Bug 2546520 (CVE-2026-98244)

Summary: CVE-2026-98244 kernel: btrfs: clear free space tree creation state on rebuild failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Btrfs file system. When an error occurs while rebuilding the free space tree, the kernel fails to properly reset an internal state flag on failure paths. A local user could exploit this condition during filesystem operations, leaving the flag set on an active file system and causing delayed reference processing to be skipped. This issue can result in filesystem metadata inconsistency, data corruption, or a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-06 09:37:59 UTC
In the Linux kernel, the following vulnerability has been resolved:

btrfs: clear free space tree creation state on rebuild failure

btrfs_rebuild_free_space_tree() sets BTRFS_FS_CREATING_FREE_SPACE_TREE
before rebuilding the free space tree.  Several error paths return
without clearing this flag.

The transaction restart failure path can leave the flag set on a live
filesystem, causing delayed reference processing to be skipped. Clear it
on all free space tree rebuild failure paths. Keep
BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED set, since a failed rebuild leaves
the free space tree untrusted. Callers must fall back to extent-tree
caching.