btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74321
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:32 UTC
Updated2026-08-17 06:19:26 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs() In the beginning of the loop, we try to obtain a locked delayed ref head, if 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(), which can return an error pointer. If the error pointer is -EAGAIN we do a continue and go back to the beginning of the loop, which will not try again to call btrfs_select_ref_head() since 'locked_ref' is no longer NULL but it's ERR_PTR(-EAGAIN), and then we do: spin_lock(&locked_ref->lock); against a ERR_PTR(-EAGAIN) value, generating an invalid pointer dereference. Fix this by ensuring that 'locked_ref' is set to NULL when btrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count' as well, to prevent infinite looping. We do this by doing a goto to the bottom of the loop that already sets 'locked_ref' to NULL and does a cond_resched(), with an increment to 'count' right before the goto. These measures were in place before the refactoring in commit 0110a4c43451 ("btrfs: refactor __btrfs_run_delayed_refs loop") but were unintentionally lost afterwards.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.005080000 probability, percentile 0.409950000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 c372ca227e16bace86f1df1fa4ae6849e2fcfa28 git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 a71143590ce9764dbcb47617647592ff8b4d48bc git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 65770111a2d47c2b15e20b2ba92bb12198f289d4 git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 015dc4a1e0c2cba551d4620eba13d26d5081dc34 git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 ba9fa2ff5981589bb49094d3358c339b37c47f53 git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1 git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 9faa6b69ad73f03c7bde53e07d75a28822dc9a1a git Not specified
CNA Linux Linux affected 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae git Not specified
CNA Linux Linux affected 4.20 Not specified
CNA Linux Linux unaffected 4.20 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/9faa6b69ad73f03c7bde53e07d75a28822dc9a1a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a71143590ce9764dbcb47617647592ff8b4d48bc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/65770111a2d47c2b15e20b2ba92bb12198f289d4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/015dc4a1e0c2cba551d4620eba13d26d5081dc34 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c372ca227e16bace86f1df1fa4ae6849e2fcfa28 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ba9fa2ff5981589bb49094d3358c339b37c47f53 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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