jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()

Summary

CVECVE-2026-72225
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:41 UTC
Updated2026-08-23 13:16:41 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit() jbd2_journal_initialize_fast_commit() validates journal capacity by checking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS). Both j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds j_last the subtraction wraps to a large value, bypassing the bounds check. The resulting underflow corrupts j_last, j_fc_first, and j_free, leading to journal abort. Fix by checking num_fc_blks against j_last before the subtraction, returning -EFSCORRUPTED.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.001720000 probability, percentile 0.069530000 (date 2026-08-17)


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

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd aa90f00932bf572d6ef284c977c2a60b39c13bd6 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd e144ad0250f77e23e28949587b8b57e40dc3b512 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd 4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd fb9b49618ed7296ebfad62a3835da8945f727001 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd 4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd 78955fdce8ff654e6d33a2fa90882a1e7eb26330 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd a58fc10adf503969fec2007b5afe8987258046c4 git Not specified
CNA Linux Linux affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd 289a2ca0c9b7eae74f93fc213b0b971669b8683d git Not specified
CNA Linux Linux affected 5.10 Not specified
CNA Linux Linux unaffected 5.10 semver Not specified
CNA Linux Linux unaffected 5.10.266 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/fb9b49618ed7296ebfad62a3835da8945f727001 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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