Vulnerability-Lookup

GHSA-FV83-X2XW-2J55

Vulnerability from github – Published: 2026-04-08 03:32 – Updated: 2026-04-20 18:31

Details

When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool.

Severity ?

7.5 (High)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-33810"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-08T02:16:03Z",
    "severity": "HIGH"
  },
  "details": "When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool.",
  "id": "GHSA-fv83-x2xw-2j55",
  "modified": "2026-04-20T18:31:42Z",
  "published": "2026-04-08T03:32:14Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33810"
    },
    {
      "type": "WEB",
      "url": "https://go.dev/cl/763763"
    },
    {
      "type": "WEB",
      "url": "https://go.dev/issue/78332"
    },
    {
      "type": "WEB",
      "url": "https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/vuln/GO-2026-4866"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/04/19/4"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/04/20/1"
    }
  ],
  "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"
    }
  ]
}

CVE-2026-33810 (GCVE-0-2026-33810)

Vulnerability from cvelistv5 – Published: 2026-04-08 01:06 – Updated: 2026-04-20 17:23

Title

Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509

Summary

Severity ?

7.5 (High)


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

CWE

CWE-295 - Improper Certificate Validation

Assigner

References

URL

Tags

	https://go.dev/cl/763763
	https://go.dev/issue/78332
	https://groups.google.com/g/golang-announce/c/0uY…
	https://pkg.go.dev/vuln/GO-2026-4866

Impacted products

	Vendor	Product	Version
	Go standard library	crypto/x509	Affected: 1.26.0-0 , < 1.26.2 (semver)

Credits

Riyas from Saintgits College of Engineering k1rnt @1seal

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-33810",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-13T17:48:57.879958Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-13T18:20:37.411Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-04-20T17:23:21.823Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/04/19/4"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/04/20/1"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "crypto/x509",
          "product": "crypto/x509",
          "programRoutines": [
            {
              "name": "newDNSConstraints"
            },
            {
              "name": "dnsConstraints.query"
            },
            {
              "name": "Certificate.Verify"
            }
          ],
          "vendor": "Go standard library",
          "versions": [
            {
              "lessThan": "1.26.2",
              "status": "affected",
              "version": "1.26.0-0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Riyas from Saintgits College of Engineering"
        },
        {
          "lang": "en",
          "value": "k1rnt"
        },
        {
          "lang": "en",
          "value": "@1seal"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-08T01:06:56.546Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/cl/763763"
        },
        {
          "url": "https://go.dev/issue/78332"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-4866"
        }
      ],
      "title": "Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-33810",
    "datePublished": "2026-04-08T01:06:56.546Z",
    "dateReserved": "2026-03-23T20:35:32.814Z",
    "dateUpdated": "2026-04-20T17:23:21.823Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-FV83-X2XW-2J55

CVE-2026-33810 (GCVE-0-2026-33810)

Tags

Sightings

Nomenclature