Vulnerability-Lookup

CVE-2026-6331 (GCVE-0-2026-6331)

Vulnerability from cvelistv5 – Published: 2026-06-25 20:56 – Updated: 2026-06-26 13:53

Title

HMAC zero-length tag forgery in EVP_DigestVerifyFinal

Summary

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.

Severity

2.1 (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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-26 13:52 UTC

CWE

CWE-347 - Improper Verification of Cryptographic Signature

Assigner

wolfSSL icscert root

References

2 references

URL	Tags
https://github.com/wolfSSL/wolfssl/pull/10192	patch
https://www.wolfssl.com/docs/security-vulnerabilities/

Impacted products

1 product

Vendor	Product	Version	CPE status
wolfSSL	wolfSSL	Affected: 3.15.5 , ≤ 5.9.1 (semver)	guessed

Credits

Nicholas Carlini from Anthropic

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-6331

Vulnerability from fkie_nvd - Published: 2026-06-25 22:17 - Updated: 2026-06-27 19:48

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Summary

References

	URL	Tags
	facts@wolfssl.com	https://github.com/wolfSSL/wolfssl/pull/10192	Issue Tracking, Patch
	facts@wolfssl.com	https://www.wolfssl.com/docs/security-vulnerabilities/	Vendor Advisory

Impacted products

	Vendor	Product	Version
	wolfssl	wolfssl	*

JSON

To clipboard

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}

GHSA-5HPF-PC4X-3JCF

Vulnerability from github – Published: 2026-06-26 00:32 – Updated: 2026-06-27 21:30

Details

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

2.1 (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

Show details on source website

JSON

To clipboard

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  "aliases": [
    "CVE-2026-6331"
  ],
  "database_specific": {
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    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T22:17:03Z",
    "severity": "LOW"
  },
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  "id": "GHSA-5hpf-pc4x-3jcf",
  "modified": "2026-06-27T21:30:28Z",
  "published": "2026-06-26T00:32:06Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6331"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wolfSSL/wolfssl/pull/10192"
    },
    {
      "type": "WEB",
      "url": "https://www.wolfssl.com/docs/security-vulnerabilities"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ]
}

MSRC_CVE-2026-6331

Vulnerability from csaf_microsoft - Published: 2026-06-02 00:00 - Updated: 2026-07-02 14:41

Summary

HMAC zero-length tag forgery in EVP_DigestVerifyFinal

Scope

1 vulnerability in this advisory, including CVE-2026-6331.

CVE-2026-6331

Known not affected: 1 product

Open the full advisory

ubuntu-cve-2026-6331

Vulnerability from osv_ubuntu

Published

2026-06-25 22:17

Modified

2026-06-25 22:17

Summary

Details

Severity

2.1 (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

7.5 (High)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-6331	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-6331	REPORT
	https://github.com/wolfSSL/wolfssl/pull/10192	REPORT
	https://github.com/wolfSSL/wolfssl/pull/10192	REPORT
	https://www.wolfssl.com/docs/security-vulnerabilities/	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libcyassl5",
            "binary_version": "3.4.8+dfsg-1"
          },
          {
            "binary_name": "libwolfssl0",
            "binary_version": "3.4.8+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@3.4.8+dfsg-1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.4.8+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libwolfssl15",
            "binary_version": "3.13.0+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@3.13.0+dfsg-1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.10.2+dfsg-2",
        "3.12.0+dfsg-1",
        "3.12.2+dfsg-1",
        "3.13.0+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libwolfssl24",
            "binary_version": "4.3.0+dfsg-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@4.3.0+dfsg-2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.0+dfsg-2",
        "4.2.0+dfsg-1",
        "4.2.0+dfsg-2",
        "4.2.0+dfsg-3",
        "4.3.0+dfsg-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libwolfssl32",
            "binary_version": "5.2.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@5.2.0-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.6.0-3",
        "5.0.0-1",
        "5.1.1-1",
        "5.2.0-1",
        "5.2.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libwolfssl42t64",
            "binary_version": "5.6.6-1.3build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@5.6.6-1.3build1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.5.4-2",
        "5.5.4-2.1",
        "5.6.4-2",
        "5.6.6-1.2",
        "5.6.6-1.3",
        "5.6.6-1.3build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libwolfssl42t64",
            "binary_version": "5.7.2-0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@5.7.2-0.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.7.2-0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libwolfssl44",
            "binary_version": "5.9.1-0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "wolfssl",
        "purl": "pkg:deb/ubuntu/wolfssl@5.9.1-0.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.7.2-0.1",
        "5.8.2-1.2",
        "5.8.4-1",
        "5.9.1-0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2026-6331",
  "modified": "2026-06-25T22:17:00Z",
  "published": "2026-06-25T22:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-6331"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-6331"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/wolfSSL/wolfssl/pull/10192"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/wolfSSL/wolfssl/pull/10192"
    },
    {
      "type": "REPORT",
      "url": "https://www.wolfssl.com/docs/security-vulnerabilities/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-6331"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-6331 (GCVE-0-2026-6331)

FKIE_CVE-2026-6331

GHSA-5HPF-PC4X-3JCF

MSRC_CVE-2026-6331

ubuntu-cve-2026-6331

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature

Related by attack behaviour