{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6331","assignerOrgId":"50d2cd11-d01a-48ed-9441-5bfce9d63b27","state":"PUBLISHED","assignerShortName":"wolfSSL","dateReserved":"2026-04-15T03:08:31.649Z","datePublished":"2026-06-25T20:56:25.876Z","dateUpdated":"2026-06-26T13:53:06.730Z"},"containers":{"cna":{"providerMetadata":{"orgId":"50d2cd11-d01a-48ed-9441-5bfce9d63b27","shortName":"wolfSSL","dateUpdated":"2026-06-25T20:56:25.876Z"},"title":"HMAC zero-length tag forgery in EVP_DigestVerifyFinal","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-347","description":"CWE-347 Improper Verification of Cryptographic Signature","type":"CWE"}]}],"affected":[{"vendor":"wolfSSL","product":"wolfSSL","collectionURL":"https://github.com/wolfSSL/wolfssl","versions":[{"status":"affected","version":"3.15.5","lessThanOrEqual":"5.9.1","versionType":"semver"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"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.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>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.</p>"}]}],"references":[{"url":"https://github.com/wolfSSL/wolfssl/pull/10192","tags":["patch"]},{"url":"https://www.wolfssl.com/docs/security-vulnerabilities/"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"LOW","baseScore":2.1,"vectorString":"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"}}],"credits":[{"lang":"en","value":"Nicholas Carlini from Anthropic","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.2"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-26T13:52:52.624679Z","id":"CVE-2026-6331","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-26T13:53:06.730Z"}}]}}