{"id":"CVE-2026-72367","title":"iomap: guard io_size EOF trim against concurrent truncate underflow","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\niomap: guard io_size EOF trim against concurrent truncate underflow\n\niomap: fix zero padding data issue in concurrent append writes\nchanged ioend accounting so that io_…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 82c59a86a247a8970d353d10f52a37e5564fb137 < cc1d6af0bee27d6595908b497424f338161299fc","Linux >= 51d20d1dacbec589d459e11fc88fbca419f84a99 < 1f38f65bf965fce9aa159d45c5347538f56c5973","Linux >= 51d20d1dacbec589d459e11fc88fbca419f84a99 < 7f7780abb4c0fdc9a2603aea8e985ff14ee900e0","Linux >= 51d20d1dacbec589d459e11fc88fbca419f84a99 < 55ec50d046c03b3724741957f7b007856e36dbe7","Linux >= 6.12.10 < 6.12.114","Linux 6.13"],"published":"2026-08-15","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:44:42.934Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72367","references":[{"url":"https://git.kernel.org/stable/c/cc1d6af0bee27d6595908b497424f338161299fc"},{"url":"https://git.kernel.org/stable/c/1f38f65bf965fce9aa159d45c5347538f56c5973"},{"url":"https://git.kernel.org/stable/c/7f7780abb4c0fdc9a2603aea8e985ff14ee900e0"},{"url":"https://git.kernel.org/stable/c/55ec50d046c03b3724741957f7b007856e36dbe7"}],"tags":["cve.org"],"epss":0.00581,"epssPercentile":0.46771,"ingestedAt":"2026-10-21T12:48:53.590Z","slug":"CVE-2026-72367","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\niomap: guard io_size EOF trim against concurrent truncate underflow\n\niomap: fix zero padding data issue in concurrent append writes\nchanged ioend accounting so that io_size tracks only valid data\nwithin EOF.  This trims io_size when a writeback range extends\npast end_pos:\n\n    ioend->io_size += map_len;\n    if (ioend->io_offset + ioend->io_size > end_pos)\n        ioend->io_size = end_pos - ioend->io_offset;\n\nHowever, if end_pos ends up below ioend->io_offset, the subtraction\nbecomes negative and is stored in size_t io_size, causing an unsigned\nwrap to a huge value.  This can happen when writeback continues past\nbyte-level EOF up to a block-aligned range, or when a concurrent\ntruncate shrinks the file after end_pos was sampled in\niomap_writeback_handle_eof().\n\nA wrapped io_size can mislead append detection and corrupt\ncompletion-time size handling, since filesystem end_io paths consume\nio_size for decisions such as on-disk EOF updates and unwritten/COW\ncompletion ranges.\n\nFix this by clamping io_size to zero when EOF has moved to or before\nthe ioend start offset.  This preserves the original intent of trimming\nio_size to valid in-EOF data while avoiding the underflow.\n\n## Affected\n\n- `Linux >= 82c59a86a247a8970d353d10f52a37e5564fb137 < cc1d6af0bee27d6595908b497424f338161299fc`\n- `Linux >= 51d20d1dacbec589d459e11fc88fbca419f84a99 < 1f38f65bf965fce9aa159d45c5347538f56c5973`\n- `Linux >= 51d20d1dacbec589d459e11fc88fbca419f84a99 < 7f7780abb4c0fdc9a2603aea8e985ff14ee900e0`\n- `Linux >= 51d20d1dacbec589d459e11fc88fbca419f84a99 < 55ec50d046c03b3724741957f7b007856e36dbe7`\n- `Linux >= 6.12.10 < 6.12.114`\n- `Linux 6.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":49,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}