{"api_version":"1","generated_at":"2026-08-22T01:48:57+00:00","cve":"CVE-2026-72367","urls":{"html":"https://cve.report/CVE-2026-72367","api":"https://cve.report/api/cve/CVE-2026-72367.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72367","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72367"},"summary":{"title":"iomap: guard io_size EOF trim against concurrent truncate underflow","description":"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_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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:10","updated_at":"2026-08-17 06:18:40"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/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/55ec50d046c03b3724741957f7b007856e36dbe7","name":"https://git.kernel.org/stable/c/55ec50d046c03b3724741957f7b007856e36dbe7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7f7780abb4c0fdc9a2603aea8e985ff14ee900e0","name":"https://git.kernel.org/stable/c/7f7780abb4c0fdc9a2603aea8e985ff14ee900e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1f38f65bf965fce9aa159d45c5347538f56c5973","name":"https://git.kernel.org/stable/c/1f38f65bf965fce9aa159d45c5347538f56c5973","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72367","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72367","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51d20d1dacbec589d459e11fc88fbca419f84a99 1f38f65bf965fce9aa159d45c5347538f56c5973 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51d20d1dacbec589d459e11fc88fbca419f84a99 7f7780abb4c0fdc9a2603aea8e985ff14ee900e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51d20d1dacbec589d459e11fc88fbca419f84a99 55ec50d046c03b3724741957f7b007856e36dbe7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 82c59a86a247a8970d353d10f52a37e5564fb137 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.10 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.13","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.13 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":"72367","cve":"CVE-2026-72367","epss":"0.005820000","percentile":"0.450160000","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/iomap/ioend.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"1f38f65bf965fce9aa159d45c5347538f56c5973","status":"affected","version":"51d20d1dacbec589d459e11fc88fbca419f84a99","versionType":"git"},{"lessThan":"7f7780abb4c0fdc9a2603aea8e985ff14ee900e0","status":"affected","version":"51d20d1dacbec589d459e11fc88fbca419f84a99","versionType":"git"},{"lessThan":"55ec50d046c03b3724741957f7b007856e36dbe7","status":"affected","version":"51d20d1dacbec589d459e11fc88fbca419f84a99","versionType":"git"},{"status":"affected","version":"82c59a86a247a8970d353d10f52a37e5564fb137","versionType":"git"},{"lessThan":"6.13","status":"affected","version":"6.12.10","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/iomap/ioend.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.13"},{"lessThan":"6.13","status":"unaffected","version":"0","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":"6.18.40","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.10","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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_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."}],"metrics":[{"cvssV3_1":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - On XFS/GFS2/NTFS backends exposed via nfsd or ksmbd, a remote client can trigger iomap buffered writeback by issuing concurrent WRITE and truncate/SETATTR operations over the network without local shell access.\nAC:L - The attacker controls both sides of the race by concurrently writing dirty pages and truncating the same file (local threads or parallel NFS/SMB requests); no uncontrollable memory layout or rare kernel configuration is required.\nPR:L - Exploitation requires write and truncate permission on the target file (authenticated NFS/SMB client or local unprivileged user with file write access); this is not a pre-authentication network code path.\nUI:N - No victim interaction is needed beyond the attacker's own write and truncate I/O; writeback is driven automatically by the VFS/page-cache path once pages are dirtied.\nS:U - Impact is confined to kernel/filesystem integrity within the same security authority (metadata corruption, incorrect extent completion, possible local privilege escalation), not a VM escape or cross-authority boundary.\nC:H - A wrapped io_size propagates into XFS completion paths (COW convert/end, unwritten conversion, append detection), potentially remapping or exposing unintended on-disk extents and data beyond the legitimate EOF-trimmed range.\nI:H - Huge bogus io_size drives xfs_reflink_convert_cow, xfs_reflink_end_cow, xfs_iomap_write_unwritten, and xfs_setfilesize with corrupted ranges, enabling incorrect on-disk metadata updates and file content modification.\nA:H - Corrupted ioend accounting can trigger pathological XFS extent walks, ASSERT failures, filesystem shutdown, or hung writeback during I/O completion, causing kernel oops or sustained denial of service."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:43:20.980Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/1f38f65bf965fce9aa159d45c5347538f56c5973"},{"url":"https://git.kernel.org/stable/c/7f7780abb4c0fdc9a2603aea8e985ff14ee900e0"},{"url":"https://git.kernel.org/stable/c/55ec50d046c03b3724741957f7b007856e36dbe7"}],"title":"iomap: guard io_size EOF trim against concurrent truncate underflow","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72367","datePublished":"2026-08-15T05:56:04.669Z","dateReserved":"2026-08-09T03:40:39.922Z","dateUpdated":"2026-08-17T05:43:20.980Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:22:10","lastModifiedDate":"2026-08-17 06:18:40","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72367","Ordinal":"1","Title":"iomap: guard io_size EOF trim against concurrent truncate underf","CVE":"CVE-2026-72367","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72367","Ordinal":"1","NoteData":"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_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.","Type":"Description","Title":"iomap: guard io_size EOF trim against concurrent truncate underf"}]}}}