{"id":"CVE-2026-99063","revision":"23c85e4ad0a3441080d354e11e683e38","records":[{"revision":"23c85e4ad0a3441080d354e11e683e38","observedAt":"2026-10-23T16:01:20.601+00:00","statement":{"source":"cve-program","id":"CVE-2026-99063","aliases":[],"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":0,"publishedAt":"2026-10-23T12:23:04.655+00:00","modifiedAt":"2026-10-23T12:23:04.655+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/md/dm-ioctl.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"76c072b48e39e9291fbf02d6c912cf27d65e093d\",\n                            \"lessThan\": \"98195e822343a656b92e235847ab3e72b1a3f920\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"76c072b48e39e9291fbf02d6c912cf27d65e093d\",\n                            \"lessThan\": \"e5c3f3d8935ecc64c962fb66e6a86dbf79218f61\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"76c072b48e39e9291fbf02d6c912cf27d65e093d\",\n                            \"lessThan\": \"5680b6fb3054677d4ee65d3baba24b649f1b430e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"76c072b48e39e9291fbf02d6c912cf27d65e093d\",\n                            \"lessThan\": \"725b49c689bbb29ef740b0d6b5ea9390baa9a695\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"76c072b48e39e9291fbf02d6c912cf27d65e093d\",\n                            \"lessThan\": \"9b3fcf519d370df94a56f3b272d9eddffffa5be8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/md/dm-ioctl.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.25\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.25\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.160\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.113\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.57\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.11\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920","https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61","https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e","https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695","https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99063","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-99063","identifiers":["CVE-2026-99063"]},"retained":false,"historicalAffected":[]}],"coverage":[]}