{"id":"RUSTSEC-2026-0312","summary":"Excluded iPAddress name constraints with an all-zero mask are not applied","details":"An `excluded_subtrees` iPAddress name constraint with an all-zero mask\n(`0.0.0.0/0` or `::/0`) does not restrict iPAddress SANs in certificates issued\nbeneath it. The mask check treated an all-zero mask as matching nothing, when a\n`/0` prefix matches every address of its family, so the exclusion was silently\nignored.\n\nCA/Browser Forum Baseline Requirements §7.1.2.5.2 require exactly these\nexclusions on every technically constrained sub-CA that may not issue for IP\naddresses. As a result, anyone holding (or having compromised) the key of such\na sub-CA can issue a certificate for an arbitrary IP address, and `Validator`\nwith `RFC5280Policy` and `ServerIdentityPolicy` accepts it for that address. A\n`permitted_subtrees` dNSName entry on the same issuer does not prevent this,\nbecause iPAddress SANs are a different name form.\n\nAll users of `Validator` with `RFC5280Policy` are affected when a chain can\ncontain a name-constrained issuer with an all-zero iPAddress exclusion.\n\nThe issue is fixed in x509-validator 0.3.1 (commit\n[da661f8](https://github.com/namecare/x509-validator/commit/da661f8ecee820e05d089a76ecb654ff52a2c987)).\nUsers should upgrade to 0.3.1 or later.","aliases":["GHSA-39mm-4q6x-3vrx"],"modified":"2026-09-28T09:45:02.969451461Z","published":"2026-09-24T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/x509-validator"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0312.html"},{"type":"WEB","url":"https://github.com/namecare/x509-validator/commit/da661f8ecee820e05d089a76ecb654ff52a2c987"}],"affected":[{"package":{"name":"x509-validator","ecosystem":"crates.io","purl":"pkg:cargo/x509-validator"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.3.1"}]}],"ecosystem_specific":{"affected_functions":null,"affects":{"arch":[],"os":[],"functions":[]}},"database_specific":{"categories":["crypto-failure"],"cvss":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","informational":null,"source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0312.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}