{"id":"CVE-2026-89492","summary":"ocfs2: validate directory-index entry counts when reading metadata","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: validate directory-index entry counts when reading metadata\n\nocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() check the ECC and\nsignature of an indexed-directory block before it reaches higher-level\ncallers, but neither validator bounds the ocfs2_dx_entry_list counts\nagainst the capacity of the block that holds them.\n\nocfs2_dx_dir_search() then walks\n\n\tfor (i = 0; i \u003c le16_to_cpu(entry_list-\u003ede_num_used); i++)\n\t\tdx_entry = &entry_list-\u003ede_entries[i];\n\nover de_num_used entries with no bounds check.  entry_list is either\ndx_leaf-\u003edl_list (from ocfs2_read_dx_leaf) or, for an inline root,\ndx_root-\u003edr_entries.  A crafted on-disk image can set de_num_used (and\nde_count, which is the __counted_by_le() bound of de_entries) to 0xffff\nand make the walk read far past the end of the 4KB metadata block, giving\na slab out-of-bounds read reachable from any path lookup, stat() or open()\non an indexed directory once the image is mounted.\n\nCommit 775c17386a6f (\"ocfs2: validate dx_root extent list fields during\nblock read\") already bounds dr_list for the non-inline dx_root, but left\nthe inline dr_entries path and the dx_leaf dl_list unchecked.  Add the\nsame read-time validation for both entry lists: de_count must equal the\ncapacity of the block (ocfs2_dx_entries_per_leaf()/per_root()) and\nde_num_used must not exceed de_count, rejecting corrupted metadata with\n-EFSCORRUPTED before ocfs2_dx_dir_search() can walk an out-of-range entry\narray.\n\nde_count is always written as exactly the block capacity when a leaf or\ninline root is formatted, so the equality check does not reject any valid\nimage.\n\nFound by 0sec automated security-research tooling (https://0sec.ai).","modified":"2026-09-13T03:47:18.498723277Z","published":"2026-09-11T19:43:44.137Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89492.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/b8a5c0c32df2c5b685ceef76ac77e37c7e1dc3ed"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bc70726ddad53c7e9a9a85915bf2415b0d4f42f9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fcfcba8fe17dbf2c8805690b8cc25e32d81249a4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89492.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89492"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"9b7895efac906d66d19856194e1ba61f37e231a4"},{"fixed":"fcfcba8fe17dbf2c8805690b8cc25e32d81249a4"},{"fixed":"b8a5c0c32df2c5b685ceef76ac77e37c7e1dc3ed"},{"fixed":"bc70726ddad53c7e9a9a85915bf2415b0d4f42f9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89492.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.30"},{"fixed":"6.18.51"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89492.json"}}],"schema_version":"1.9.0"}