{"id":"CVE-2026-6331","summary":"HMAC zero-length tag forgery in EVP_DigestVerifyFinal","details":"HMAC zero-length tag forgery in EVP_DigestVerifyFinal, where a zero-length tag could be accepted as valid during HMAC verification. In the OpenSSL-compatibility HMAC verify path the supplied signature length was only checked as not exceeding the MAC length, so a zero-length or otherwise truncated tag could pass verification. The fix requires the supplied tag length to exactly equal the MAC length and rejects a zero-length MAC, so a forged short or empty tag is no longer accepted.","modified":"2026-07-16T03:48:47.563118791Z","published":"2026-06-25T20:56:25.876Z","database_specific":{"cna_assigner":"wolfSSL","cwe_ids":["CWE-347"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6331.json"},"references":[{"type":"WEB","url":"https://www.wolfssl.com/docs/security-vulnerabilities/"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6331.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6331"},{"type":"FIX","url":"https://github.com/wolfSSL/wolfssl/pull/10192"},{"type":"PACKAGE","url":"https://github.com/wolfSSL/wolfssl"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/wolfssl/wolfssl","events":[{"introduced":"11810160b47ad37968fea375bdc6ad26b9973cd5"},{"fixed":"ac01707f552c611fbd135cc723b2682b3e7f80f2"}],"database_specific":{"extracted_events":[{"introduced":"3.15.5"},{"last_affected":"5.9.1"},{"fixed":"5.9.2"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*"}}],"versions":["v5.9.1-stable","v5.9.0-stable","v5.8.4-stable","wolfEntropy2d","v5.8.2-stable","wolfEntropy1","v5.8.0-stable","v5.7.6-stable","v5.7.4-stable","v5.2.1","v5.7.2-stable","v5.7.0-stable","v5.6.6-stable","v5.6.4-stable","WCv5.0-RC12","WCv5.0-RC11","WCv5.0-RC10","v5.6.2-stable","v5.6.3-stable","v5.6.0-stable","v5.5.4-stable","v5.5.3-stable","v5.5.2-stable","v5.5.1-stable","v5.5.0-stable","v5.4.0-stable","v5.3.0-stable","v5.2.0-stable","v5.1.0-stable","v5.0.0-stable","WCv5.0-RC9","v4.8.0-stable","v4.7.1r","v4.7.0-stable","v4.6.0-stable","v4.5.0-stable","v4.4.0-stable","v4.3.0-stable","v4.2.0c","v4.2.0-stable","v4.1.0-stable","v4.0.0-stable","list","v3.15.7-stable","v3.15.6","v3.15.5a"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-6331.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"}]}