btrfs: fix extent map leak in NOCOW direct I/O write

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89644
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:50 UTC
Updated2026-09-21 14:17:24 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: btrfs: fix extent map leak in NOCOW direct I/O write btrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an extent map reference that must be dropped on all exit paths. For direct writes into a NOCOW range, btrfs_get_blocks_direct_write() keeps using that extent map and asks btrfs_create_dio_extent() to allocate the ordered extent. If that fails, for example because btrfs_alloc_ordered_extent() fails, the function returns the error without dropping the input extent map. The PREALLOC path avoided this by dropping the input extent map before replacing it with the newly created one. Check the error from btrfs_create_dio_extent() before replacing the map and drop the input extent map on failure.

Risk And Classification

EPSS: 0.001680000 probability, percentile 0.064510000 (date 2026-09-22)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af b7c873765875645b11503f94c9bae2ca80127375 git Not specified
CNA Linux Linux affected 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2 git Not specified
CNA Linux Linux affected 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af 05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d git Not specified
CNA Linux Linux affected 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af 3f950867c307c5413d628a153ac44915bd117ffd git Not specified
CNA Linux Linux affected 4.7 Not specified
CNA Linux Linux unaffected 4.7 semver Not specified
CNA Linux Linux unaffected 6.12.111 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/3f950867c307c5413d628a153ac44915bd117ffd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b7c873765875645b11503f94c9bae2ca80127375 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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