AUGUST 16, 2026
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Case File

CVE-2026-6331

HIGH · CVSS 7.5 EPSS 0.15% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-06-25 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 7.5. It affects OpenSSL. Public exploit code or proof-of-concept references have been detected in its references.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-6331
Severity
HIGH
CVSS
7.5
EPSS
0.15%
OpenSSL

Original NVD 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.

Related CVEs

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