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

Vulnerability from cvelistv5 – Published: 2026-04-08 01:06 – Updated: 2026-04-20 17:23
VLAI
Title
Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509
Summary
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
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-295 - Improper Certificate Validation
Assigner
Go
References
Impacted products
Vendor Product Version
Go standard library crypto/x509 Affected: 1.26.0-0 , < 1.26.2 (semver)
Create a notification for this product.
Credits
Riyas from Saintgits College of Engineering k1rnt @1seal
Show details on NVD website
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",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-33810",
      "date": "2026-06-07",
      "epss": "0.00013",
      "percentile": "0.02379"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-33810\",\"sourceIdentifier\":\"security@golang.org\",\"published\":\"2026-04-08T02:16:03.950\",\"lastModified\":\"2026-04-20T18:16:26.813\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"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.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N\",\"baseScore\":8.2,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":4.2},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-295\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.26.0\",\"versionEndExcluding\":\"1.26.2\",\"matchCriteriaId\":\"39FE9BAF-55E9-43AA-B14E-239E7EF1D65D\"}]}]}],\"references\":[{\"url\":\"https://go.dev/cl/763763\",\"source\":\"security@golang.org\",\"tags\":[\"Patch\"]},{\"url\":\"https://go.dev/issue/78332\",\"source\":\"security@golang.org\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU\",\"source\":\"security@golang.org\",\"tags\":[\"Mailing List\",\"Release Notes\"]},{\"url\":\"https://pkg.go.dev/vuln/GO-2026-4866\",\"source\":\"security@golang.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/04/19/4\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/04/20/1\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"http://www.openwall.com/lists/oss-security/2026/04/19/4\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2026-04-19T22:08:53.727Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-33810\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-13T17:48:57.879958Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-13T17:48:52.707Z\"}}], \"cna\": {\"title\": \"Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509\", \"credits\": [{\"lang\": \"en\", \"value\": \"Riyas from Saintgits College of Engineering\"}, {\"lang\": \"en\", \"value\": \"k1rnt\"}, {\"lang\": \"en\", \"value\": \"@1seal\"}], \"affected\": [{\"vendor\": \"Go standard library\", \"product\": \"crypto/x509\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.26.0-0\", \"lessThan\": \"1.26.2\", \"versionType\": \"semver\"}], \"packageName\": \"crypto/x509\", \"collectionURL\": \"https://pkg.go.dev\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"newDNSConstraints\"}, {\"name\": \"dnsConstraints.query\"}, {\"name\": \"Certificate.Verify\"}]}], \"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\"}], \"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\": [{\"lang\": \"en\", \"description\": \"CWE-295: Improper Certificate Validation\"}]}], \"providerMetadata\": {\"orgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"shortName\": \"Go\", \"dateUpdated\": \"2026-04-08T01:06:56.546Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-33810\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-19T22:08:53.727Z\", \"dateReserved\": \"2026-03-23T20:35:32.814Z\", \"assignerOrgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"datePublished\": \"2026-04-08T01:06:56.546Z\", \"assignerShortName\": \"Go\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.