{"id":"CVE-2026-99112","aliases":[],"title":"net/sched: cls_flower: validate mask pointer after nla_next()","titleSource":"Linux","descriptionSource":"Linux","products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"c96adff95619178e2118925578343ad54857c80c","status":"affected","lessThan":"45e60747a9db2307929260d9aa9c1c6cbb70ee77","versionType":"git"},{"version":"c96adff95619178e2118925578343ad54857c80c","status":"affected","lessThan":"bb187146c7e5c666874784e4f3fc1bc5126e6e92","versionType":"git"},{"version":"c96adff95619178e2118925578343ad54857c80c","status":"affected","lessThan":"fee10655709c5c597e8e9f722f3035d9ea31ff3a","versionType":"git"},{"version":"238b5ebdb6a6e4bc90810b9f8ec0063b3dfda41a","status":"affected","versionType":"git"},{"version":"5.10.11","status":"affected","lessThan":"5.11","versionType":"semver"}],"defaultStatus":"unaffected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99112"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"5.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.11","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99112"}],"remediation":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_flower: validate mask pointer after nla_next()\n\nfl_set_enc_opt() iterates the key's nested tunnel-option attributes\nwith nla_for_each_attr() while advancing a single mask pointer via\nnla_next() at the bottom of each loop, so the mask cursor is driven\nby the number of key attributes rather than by the mask's own\nattributes.  The nla_ok() added by commit c96adff956191 (\"cls_flower:\ncall nla_ok() before nla_next()\") only validates the mask pointer\nthat was just consumed; the pointer produced by nla_next() is used by\nthe next iteration (fl_set_geneve_opt() and siblings) without any\nvalidation.\n\nThe mask's nested attributes are validated with NL_VALIDATE_LIBERAL,\nwhich merely warns on trailing bytes that do not form a complete\nattribute.  A mask carrying one valid attribute plus 1-3 residue\nbytes (or a non-aligned attribute length making msk_depth negative)\ntherefore reaches the next iteration with msk_depth != 0, so neither\nthe !msk_depth check in fl_set_enc_opt() nor the !depth check in the\nper-type helpers fires.  nla_type() then reads past the mask payload\nand nla_parse_nested_deprecated() iterates with an nla_len taken\nfrom those bytes, reading well beyond the mask attribute (KASAN:\nslab-out-of-bounds read in __nla_validate_parse from fl_change()).\n\nValidate the advanced mask pointer as well: when the mask is not\nlegitimately exhausted (msk_depth != 0) and the new pointer fails\nnla_ok(), reject the filter with -EINVAL.  An exactly exhausted mask\nstill skips the check, preserving exact-match behaviour for the\nremaining key attributes.","severity":"unknown","score":null,"published":"2026-10-28T10:34:29.881Z","modified":"2026-10-28T10:34:29.881Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://git.kernel.org/stable/c/45e60747a9db2307929260d9aa9c1c6cbb70ee77","https://git.kernel.org/stable/c/bb187146c7e5c666874784e4f3fc1bc5126e6e92","https://git.kernel.org/stable/c/fee10655709c5c597e8e9f722f3035d9ea31ff3a"],"sources":[{"name":"CVE","id":"CVE-2026-99112","modified":"2026-10-28T10:34:29.881Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-99112"}],"assessments":[],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T22:10:31.402Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}