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.
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History
Thu, 25 Jun 2026 21:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | HMAC zero-length tag forgery in EVP_DigestVerifyFinal | |
| Weaknesses | CWE-347 | |
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cvssV4_0
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MITRE
Status: PUBLISHED
Assigner: wolfSSL
Published:
Updated: 2026-06-25T20:56:25.876Z
Reserved: 2026-04-15T03:08:31.649Z
Link: CVE-2026-6331
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
Updated: 2026-06-25T22:30:15Z