{"schema":"threatline.record/2","record":{"id":"CVE-2026-97555","aliases":[],"summary":"smb: client: fix heap overflow in DACL owner/group rewrite","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in DACL owner/group rewrite\n\nWhen id_mode_to_cifs_acl rewrites an existing DACL, it allocates a\nbuffer sized according to the on-disk DACL length reported by\ndacl_ptr->size. However, replace_sids_and_copy_aces may rewrite each\nACE with a new owner/group SID obtained from the cifs.idmap upcall.\nThose SIDs can have up to SID_MAX_SUB_AUTHORITIES (15) sub-authorities,\nmaking each ACE up to 76 bytes (sizeof(struct smb_ace)).\n\nIf the original DACL contains short SIDs (e.g., 1 sub-authority) while\nthe replacement SIDs are long, the rewritten ACEs overflow the\nallocation.\n\nFix this by always budgeting for worst-case SID expansion: allocate\nsizeof(struct smb_acl) plus num_aces * sizeof(struct smb_ace), which\ncovers the smb_acl header and room for every ACE at maximum SID size.\nThis replaces the previous split logic that used dacl_ptr->size for\ncifsacl mounts but num_aces * sizeof(struct smb_ace) for mode_from_sid\nmounts: both paths can trigger the same rewrite and need the same\nheadroom.\n\nKASAN reports this as:\n  BUG: KASAN: slab-out-of-bounds in build_sec_desc+0x1e8a/0x2680 [cifs]\n  Write of size 4 at addr ffff8881a5e25374 by task chown/5298\n  ...\n  The buggy address is located 0 bytes to the right of\n   allocated 884-byte region [ffff8881a5e25000, ffff8881a5e25374)","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97555","source_modified_at":"2026-10-19T09:09:18.287Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"bc3e9dd9d104ca1b75644eab87b38ce8a924aef4","lessThan":"d5cea6766ae1868a51c7d17d77d065b4f55c587f","status":"affected","versionType":"git"},{"version":"bc3e9dd9d104ca1b75644eab87b38ce8a924aef4","lessThan":"fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1","status":"affected","versionType":"git"},{"version":"bc3e9dd9d104ca1b75644eab87b38ce8a924aef4","lessThan":"7fa84c9ca690643f429ae2709584a47e74b572c9","status":"affected","versionType":"git"},{"version":"bc3e9dd9d104ca1b75644eab87b38ce8a924aef4","lessThan":"2a9aee9ef5622d58d8aafaa3263b3ffe70e2d9dd","status":"affected","versionType":"git"},{"version":"bc3e9dd9d104ca1b75644eab87b38ce8a924aef4","lessThan":"0ee150794c75bcd0be0e24ff3394f433cbae18cc","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97555","source_modified_at":"2026-10-19T09:09:18.287Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.12","status":"affected"},{"version":"0","lessThan":"5.12","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97555","source_modified_at":"2026-10-19T09:09:18.287Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"7fa84c9ca690643f429ae2709584a47e74b572c9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97555","source_modified_at":"2026-10-19T09:09:18.287Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"2a9aee9ef5622d58d8aafaa3263b3ffe70e2d9dd","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97555","source_modified_at":"2026-10-19T09:09:18.287Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"0ee150794c75bcd0be0e24ff3394f433cbae18cc","basis":"first unaffected version stated in the CVE record"}],"cvss":8.8,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00524,"percentile":0.43667,"score_date":"2026-10-23"},"published_at":"2026-09-25T10:21:46.445Z","modified_at":"2026-10-19T09:09:18.287Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-97555","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:09:18.287Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-97555","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/d5cea6766ae1868a51c7d17d77d065b4f55c587f"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/7fa84c9ca690643f429ae2709584a47e74b572c9"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/2a9aee9ef5622d58d8aafaa3263b3ffe70e2d9dd"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/0ee150794c75bcd0be0e24ff3394f433cbae18cc"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:09:18.287Z","content_hash":"0f478a873ed846823073cfd5624be79bc8b5a47d76bb82656db66225e240079d"}}