HMAC zero-length tag forgery in EVP_DigestVerifyFinal_CVE-2026-6331

2.1 / 10

LOW

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

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.

Basic Information

ID CVE-2026-6331

Source wolfSSL

Published Jun 25, 2026 at 20:56

Affected Product

Vendor wolfSSL

Product wolfSSL

Version 3.15.5

Affected Versions wolfSSL wolfSSL 3.15.5

CWE Classification

CWE-347

References

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    "published": "2026-06-25T20:56:25.876Z",
    "modified": "2026-06-25T20:56:25.876Z",
    "type": "cve",
    "title": "HMAC zero-length tag forgery in EVP_DigestVerifyFinal",
    "source": "wolfSSL",
    "references": "https://github.com/wolfSSL/wolfssl/pull/10192\nhttps://www.wolfssl.com/docs/security-vulnerabilities/",
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