CVE-2026-6331
HMAC zero-length tag forgery in EVP_DigestVerifyFinal
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.
INFO
Published Date :
June 25, 2026, 8:56 p.m.
Last Modified :
June 25, 2026, 8:56 p.m.
Remotely Exploit :
No
Source :
wolfSSL
Affected Products
The following products are affected by CVE-2026-6331
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | LOW | 50d2cd11-d01a-48ed-9441-5bfce9d63b27 |
Solution
- Ensure tag length exactly matches MAC length.
- Reject zero-length MAC tags.
- Update OpenSSL to a version with the fix.
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The following list is the news that have been mention
CVE-2026-6331 vulnerability anywhere in the article.