{"id":"CVE-2026-72225","title":"jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()","summary":"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 - nu…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < aa90f00932bf572d6ef284c977c2a60b39c13bd6","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < e144ad0250f77e23e28949587b8b57e40dc3b512","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < fb9b49618ed7296ebfad62a3835da8945f727001","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 78955fdce8ff654e6d33a2fa90882a1e7eb26330","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < a58fc10adf503969fec2007b5afe8987258046c4","Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 289a2ca0c9b7eae74f93fc213b0b971669b8683d","Linux 5.10"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T18:44:09.066812Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:45:02.597Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72225","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"}],"tags":["cve.org"],"epss":0.00177,"epssPercentile":0.06789,"ingestedAt":"2026-10-16T19:46:24.421Z","slug":"CVE-2026-72225","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < aa90f00932bf572d6ef284c977c2a60b39c13bd6`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < e144ad0250f77e23e28949587b8b57e40dc3b512`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < fb9b49618ed7296ebfad62a3835da8945f727001`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 78955fdce8ff654e6d33a2fa90882a1e7eb26330`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < a58fc10adf503969fec2007b5afe8987258046c4`\n- `Linux >= 6866d7b3f2bb4f011041ba54c98b1584497fe2fd < 289a2ca0c9b7eae74f93fc213b0b971669b8683d`\n- `Linux 5.10`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}