{"id":"CVE-2026-97926","revision":"696727b053b64ab6be98e3ec1cf3777a","records":[{"revision":"696727b053b64ab6be98e3ec1cf3777a","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-97926","aliases":[],"title":"ufs: validate cylinder group metadata before caching it","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nufs: validate cylinder group metadata before caching it\n\nufs_read_cylinder() copies the cylinder group index and the rotor\npositions straight from the on-disk group and caches them without any\ncheck:\n\n\tucpi->c_cgx    = fs32_to_cpu(sb, ucg->cg_cgx);\n\tucpi->c_rotor  = fs32_to_cpu(sb, ucg->cg_rotor);\n\tucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor);\n\tucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor);\n\nThey are then used as indices during allocation and free:\n\n  - c_cgx indexes the cylinder summary array as\n    UFS_SB(sb)->fs_cs(ucpi->c_cgx), so a value past s_ncg writes a 32\n    bit count outside the s_csp allocation.\n\n  - c_frotor becomes a bitmap scan start, start = c_frotor >> 3, and\n    then length = ((s_fpg + 7) >> 3) - start. A start beyond the block\n    bitmap wraps the unsigned length to a huge value, so ubh_scanc()\n    walks far past the cylinder group buffers. c_irotor drives the\n    inode bitmap the same way.\n\nA crafted image can set any of these freely, turning an ordinary\nallocation into an out of bounds access.\n\nReject a cylinder group whose recorded index does not match the group\nbeing read, or whose rotors fall outside the group, before the metadata\nis cached. Valid filesystems keep cg_cgx equal to the group number and\nthe rotors within the group, so only malformed images are rejected.","state":0,"publishedAt":"2026-09-25T10:22:44.197+00:00","modifiedAt":"2026-10-19T09:10:53.241+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                        \"fs/ufs/cylinder.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"88cccb6beba136b73f0caf80e59457e1b3c0ca1e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"f560a9e33365c460827c735fd86435f9213f1aed\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"e4c5cc9688c3e69d07d888853388549ae26c0521\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"58c0c414b2b8d099d33da494a354fa836ca6c10b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"5902a95066883cf96fa15b2680694fc5dd0c7d11\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"87b12dc360a002eb2d498aa4f01e84347019612d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"abde9eb33106850dfa367ad3965d3588bb8558d5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"c9d263be26806d388129fab8c6904bed197fc6af\",\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                        \"fs/ufs/cylinder.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.12\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.12\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.271\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.222\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.189\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.158\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.111\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.53\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.7\",\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":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","score":7,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/88cccb6beba136b73f0caf80e59457e1b3c0ca1e","https://git.kernel.org/stable/c/f560a9e33365c460827c735fd86435f9213f1aed","https://git.kernel.org/stable/c/e4c5cc9688c3e69d07d888853388549ae26c0521","https://git.kernel.org/stable/c/58c0c414b2b8d099d33da494a354fa836ca6c10b","https://git.kernel.org/stable/c/5902a95066883cf96fa15b2680694fc5dd0c7d11","https://git.kernel.org/stable/c/87b12dc360a002eb2d498aa4f01e84347019612d","https://git.kernel.org/stable/c/abde9eb33106850dfa367ad3965d3588bb8558d5","https://git.kernel.org/stable/c/c9d263be26806d388129fab8c6904bed197fc6af"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-97926","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-97926","identifiers":["CVE-2026-97926"]},"retained":false,"historicalAffected":[]}],"coverage":[]}