{"api_version":"1","generated_at":"2026-10-27T07:58:05+00:00","cve":"CVE-2026-99063","urls":{"html":"https://cve.report/CVE-2026-99063","api":"https://cve.report/api/cve/CVE-2026-99063.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-99063","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-99063"},"summary":{"title":"dm ioctl: don't let data_start run past the buffer","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm ioctl: don't let data_start run past the buffer\n\nstruct dm_ioctl has seven bytes of trailing padding, so the smallest\nbuffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data),\nis seven bytes shorter than sizeof(struct dm_ioctl).\n\nget_result_buffer() sets data_start to sizeof(struct dm_ioctl) without\nlooking at how big the buffer actually is. Ask for the minimum and\ndata_start ends up seven bytes past the end. Callers add it to\ndata_size, and ctl_ioctl() copies that much back to userspace:\n\n  BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0\n  Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140\n   ctl_ioctl+0x5e3/0xcb0\n   dm_ctl_ioctl+0x25/0x40\n  allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31)\n\nA DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the\nseven bytes that leak are whatever sat next to the allocation.\n\nClamp data_start to the buffer size.\n\nNote that this is not a security bug because the out-of-bounds read can\nonly be triggered by root.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-23 13:17:30","updated_at":"2026-10-23 13:17:30"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8","name":"https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e","name":"https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920","name":"https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61","name":"https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695","name":"https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-99063","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99063","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76c072b48e39e9291fbf02d6c912cf27d65e093d 98195e822343a656b92e235847ab3e72b1a3f920 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76c072b48e39e9291fbf02d6c912cf27d65e093d e5c3f3d8935ecc64c962fb66e6a86dbf79218f61 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76c072b48e39e9291fbf02d6c912cf27d65e093d 5680b6fb3054677d4ee65d3baba24b649f1b430e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76c072b48e39e9291fbf02d6c912cf27d65e093d 725b49c689bbb29ef740b0d6b5ea9390baa9a695 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76c072b48e39e9291fbf02d6c912cf27d65e093d 9b3fcf519d370df94a56f3b272d9eddffffa5be8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.25","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.25 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.160 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.113 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.57 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.11 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/md/dm-ioctl.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"98195e822343a656b92e235847ab3e72b1a3f920","status":"affected","version":"76c072b48e39e9291fbf02d6c912cf27d65e093d","versionType":"git"},{"lessThan":"e5c3f3d8935ecc64c962fb66e6a86dbf79218f61","status":"affected","version":"76c072b48e39e9291fbf02d6c912cf27d65e093d","versionType":"git"},{"lessThan":"5680b6fb3054677d4ee65d3baba24b649f1b430e","status":"affected","version":"76c072b48e39e9291fbf02d6c912cf27d65e093d","versionType":"git"},{"lessThan":"725b49c689bbb29ef740b0d6b5ea9390baa9a695","status":"affected","version":"76c072b48e39e9291fbf02d6c912cf27d65e093d","versionType":"git"},{"lessThan":"9b3fcf519d370df94a56f3b272d9eddffffa5be8","status":"affected","version":"76c072b48e39e9291fbf02d6c912cf27d65e093d","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/md/dm-ioctl.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.25"},{"lessThan":"2.6.25","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.160","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.113","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.57","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.160","versionStartIncluding":"2.6.25","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.113","versionStartIncluding":"2.6.25","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.57","versionStartIncluding":"2.6.25","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.11","versionStartIncluding":"2.6.25","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"2.6.25","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm ioctl: don't let data_start run past the buffer\n\nstruct dm_ioctl has seven bytes of trailing padding, so the smallest\nbuffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data),\nis seven bytes shorter than sizeof(struct dm_ioctl).\n\nget_result_buffer() sets data_start to sizeof(struct dm_ioctl) without\nlooking at how big the buffer actually is. Ask for the minimum and\ndata_start ends up seven bytes past the end. Callers add it to\ndata_size, and ctl_ioctl() copies that much back to userspace:\n\n  BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0\n  Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140\n   ctl_ioctl+0x5e3/0xcb0\n   dm_ctl_ioctl+0x25/0x40\n  allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31)\n\nA DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the\nseven bytes that leak are whatever sat next to the allocation.\n\nClamp data_start to the buffer size.\n\nNote that this is not a security bug because the out-of-bounds read can\nonly be triggered by root."}],"providerMetadata":{"dateUpdated":"2026-10-23T12:23:04.655Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920"},{"url":"https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61"},{"url":"https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e"},{"url":"https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695"},{"url":"https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8"}],"title":"dm ioctl: don't let data_start run past the buffer","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-99063","datePublished":"2026-10-23T12:23:04.655Z","dateReserved":"2026-09-25T10:25:14.388Z","dateUpdated":"2026-10-23T12:23:04.655Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-23 13:17:30","lastModifiedDate":"2026-10-23 13:17:30","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"99063","Ordinal":"1","Title":"dm ioctl: don't let data_start run past the buffer","CVE":"CVE-2026-99063","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"99063","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm ioctl: don't let data_start run past the buffer\n\nstruct dm_ioctl has seven bytes of trailing padding, so the smallest\nbuffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data),\nis seven bytes shorter than sizeof(struct dm_ioctl).\n\nget_result_buffer() sets data_start to sizeof(struct dm_ioctl) without\nlooking at how big the buffer actually is. Ask for the minimum and\ndata_start ends up seven bytes past the end. Callers add it to\ndata_size, and ctl_ioctl() copies that much back to userspace:\n\n  BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0\n  Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140\n   ctl_ioctl+0x5e3/0xcb0\n   dm_ctl_ioctl+0x25/0x40\n  allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31)\n\nA DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the\nseven bytes that leak are whatever sat next to the allocation.\n\nClamp data_start to the buffer size.\n\nNote that this is not a security bug because the out-of-bounds read can\nonly be triggered by root.","Type":"Description","Title":"dm ioctl: don't let data_start run past the buffer"}]}}}