Cloudanix VulnDB

CVE-2026-6331

None

CVSS

—

EPSS

0.2%

Published

Jun 25, 2026

CISA due date

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The record

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.

Affected packages

Ecosystem Package Introduced Fixed

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