{"api_version":"1","generated_at":"2026-08-23T21:53:22+00:00","cve":"CVE-2026-72225","urls":{"html":"https://cve.report/CVE-2026-72225","api":"https://cve.report/api/cve/CVE-2026-72225.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72225","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72225"},"summary":{"title":"jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\njbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()\n\njbd2_journal_initialize_fast_commit() validates journal capacity by\nchecking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS).\nBoth j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds\nj_last the subtraction wraps to a large value, bypassing the bounds\ncheck.\n\nThe resulting underflow corrupts j_last, j_fc_first, and j_free,\nleading to journal abort.\n\nFix by checking num_fc_blks against j_last before the subtraction,\nreturning -EFSCORRUPTED.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:41","updated_at":"2026-08-23 13:16:41"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/fb9b49618ed7296ebfad62a3835da8945f727001","name":"https://git.kernel.org/stable/c/fb9b49618ed7296ebfad62a3835da8945f727001","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9","name":"https://git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d","name":"https://git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330","name":"https://git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6","name":"https://git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512","name":"https://git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4","name":"https://git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6","name":"https://git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72225","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72225","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd aa90f00932bf572d6ef284c977c2a60b39c13bd6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd e144ad0250f77e23e28949587b8b57e40dc3b512 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd 4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6866d7b3f2bb4f011041ba54c98b1584497fe2fd fb9b49618ed7296ebfad62a3835da8945f727001 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"72225","cve":"CVE-2026-72225","epss":"0.001720000","percentile":"0.069530000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/jbd2/journal.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"aa90f00932bf572d6ef284c977c2a60b39c13bd6","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"e144ad0250f77e23e28949587b8b57e40dc3b512","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"fb9b49618ed7296ebfad62a3835da8945f727001","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"78955fdce8ff654e6d33a2fa90882a1e7eb26330","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"a58fc10adf503969fec2007b5afe8987258046c4","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"},{"lessThan":"289a2ca0c9b7eae74f93fc213b0b971669b8683d","status":"affected","version":"6866d7b3f2bb4f011041ba54c98b1584497fe2fd","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/jbd2/journal.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.10"},{"lessThan":"5.10","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.266","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.266","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.10","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\njbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()\n\njbd2_journal_initialize_fast_commit() validates journal capacity by\nchecking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS).\nBoth j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds\nj_last the subtraction wraps to a large value, bypassing the bounds\ncheck.\n\nThe resulting underflow corrupts j_last, j_fc_first, and j_free,\nleading to journal abort.\n\nFix by checking num_fc_blks against j_last before the subtraction,\nreturning -EFSCORRUPTED."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable code is reached only via the ext4 mount path (mount/fsopen syscall) when enabling JBD2 fast commit in jbd2_journal_set_features(); it is not reachable through network-facing kernel services.\nAC:L - An attacker who can mount a crafted ext4 image fully controls journal superblock fields (s_num_fc_blks vs s_maxlen) and can reliably trigger the underflow on first-time fast-commit enable without races or rare kernel configs.\nPR:L - Triggering ext4 mount of a malicious image requires CAP_SYS_ADMIN, which an unprivileged local user can obtain inside a user/mount namespace (e.g. unshare -Urm) to mount loop-backed ext4 with fast_commit enabled.\nUI:N - Exploitation does not require a separate victim action beyond the attacker (or their namespace) performing the mount of the prepared filesystem image; no additional user interaction is needed.\nS:U - Impact is confined to journal/ext4 corruption and I/O within the mounting kernel context; it does not cross a VM, container, or IOMMU security boundary to affect a separate authority.\nC:H - Corrupted j_last/j_fc_first/j_free values drive subsequent jbd2_journal_bmap and journal I/O with attacker-influenced block indices, enabling out-of-bounds reads from the journal backing device and potential kernel memory disclosure.\nI:H - The same corrupted journal geometry can direct journal block allocations and writes to incorrect offsets on the backing block device, constituting exploitable metadata corruption with integrity impact beyond a simple error return.\nA:H - The fix commit and jbd2 abort path confirm the corruption leads to journal abort and mount/operational failure; repeated mounting of malicious images can deny filesystem availability and force recovery or remount-readonly."}]}],"providerMetadata":{"dateUpdated":"2026-08-23T12:47:03.674Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6"},{"url":"https://git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512"},{"url":"https://git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6"},{"url":"https://git.kernel.org/stable/c/fb9b49618ed7296ebfad62a3835da8945f727001"},{"url":"https://git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9"},{"url":"https://git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330"},{"url":"https://git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4"},{"url":"https://git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d"}],"title":"jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72225","datePublished":"2026-08-15T05:54:17.541Z","dateReserved":"2026-08-09T03:40:39.913Z","dateUpdated":"2026-08-23T12:47:03.674Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:41","lastModifiedDate":"2026-08-23 13:16:41","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72225","Ordinal":"1","Title":"jbd2: fix integer underflow in jbd2_journal_initialize_fast_comm","CVE":"CVE-2026-72225","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72225","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\njbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()\n\njbd2_journal_initialize_fast_commit() validates journal capacity by\nchecking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS).\nBoth j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds\nj_last the subtraction wraps to a large value, bypassing the bounds\ncheck.\n\nThe resulting underflow corrupts j_last, j_fc_first, and j_free,\nleading to journal abort.\n\nFix by checking num_fc_blks against j_last before the subtraction,\nreturning -EFSCORRUPTED.","Type":"Description","Title":"jbd2: fix integer underflow in jbd2_journal_initialize_fast_comm"}]}}}