{
  "id": "CVE-2026-6331",
  "url": "https://spydr.io/cve/CVE-2026-6331",
  "published": "2026-06-25T22:17:03.010Z",
  "modified": "2026-06-27T19:48:56.343Z",
  "score": 2.1,
  "severity": "low",
  "cvss_version": "4.0",
  "vector": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
  "score_source": "wolfssl.com",
  "epss": 0.0019,
  "epss_percentile": 0.07856,
  "exploited": false,
  "kev": null,
  "ssvc_exploitation": "none",
  "vendors": [
    "wolfSSL"
  ],
  "products": [
    "wolfSSL"
  ],
  "cwes": [
    "CWE-347"
  ],
  "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.",
  "status": "Analyzed",
  "score_type": "Secondary",
  "scores": {
    "cvss_v40": 2.1,
    "cvss_v31": 7.5,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://github.com/wolfSSL/wolfssl/pull/10192",
      "tags": [
        "Issue Tracking",
        "Patch"
      ]
    },
    {
      "url": "https://www.wolfssl.com/docs/security-vulnerabilities/",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6331",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}