CVE-2026-27137 (GCVE-0-2026-27137)

Vulnerability from cvelistv5 – Published: 2026-03-06 21:28 – Updated: 2026-03-10 13:32
VLAI
Title
Incorrect enforcement of email constraints in crypto/x509
Summary
When verifying a certificate chain which contains a certificate containing multiple email address constraints which share common local portions but different domain portions, these constraints will not be properly applied, and only the last constraint will be considered.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 , < 1.26.1 (semver)
Create a notification for this product.
Credits
Jakub Ciolek
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-27137",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-10T13:32:09.097820Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-10T13:32:53.202Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "crypto/x509",
          "product": "crypto/x509",
          "programRoutines": [
            {
              "name": "newEmailConstraints"
            },
            {
              "name": "emailConstraints.query"
            },
            {
              "name": "checkConstraints"
            },
            {
              "name": "checkChainConstraints"
            },
            {
              "name": "parseMailboxes"
            },
            {
              "name": "Certificate.Verify"
            }
          ],
          "vendor": "Go standard library",
          "versions": [
            {
              "lessThan": "1.26.1",
              "status": "affected",
              "version": "1.26.0-0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Jakub Ciolek"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "When verifying a certificate chain which contains a certificate containing multiple email address constraints which share common local portions but different domain portions, these constraints will not be properly applied, and only the last constraint will be considered."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-08T05:56:20.771Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/cl/752182"
        },
        {
          "url": "https://go.dev/issue/77952"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/EdhZqrQ98hk"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-4599"
        }
      ],
      "title": "Incorrect enforcement of email constraints in crypto/x509"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-27137",
    "datePublished": "2026-03-06T21:28:13.748Z",
    "dateReserved": "2026-02-17T19:57:28.434Z",
    "dateUpdated": "2026-03-10T13:32:53.202Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-27137",
      "date": "2026-06-22",
      "epss": "0.00358",
      "percentile": "0.27437"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-27137\",\"sourceIdentifier\":\"security@golang.org\",\"published\":\"2026-03-06T22:16:00.850\",\"lastModified\":\"2026-04-21T14:40:31.187\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"When verifying a certificate chain which contains a certificate containing multiple email address constraints which share common local portions but different domain portions, these constraints will not be properly applied, and only the last constraint will be considered.\"},{\"lang\":\"es\",\"value\":\"Al verificar una cadena de certificados que contiene un certificado con m\u00faltiples restricciones de direcci\u00f3n de correo electr\u00f3nico que comparten porciones locales comunes pero porciones de dominio diferentes, estas restricciones no se aplicar\u00e1n correctamente, y solo la \u00faltima restricci\u00f3n ser\u00e1 considerada.\"}],\"metrics\":{\"cvssMetricV31\":[{\"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:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"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:1.26.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"A40FE3CB-0D03-462B-8A19-4DF1920ABE82\"}]}]}],\"references\":[{\"url\":\"https://go.dev/cl/752182\",\"source\":\"security@golang.org\",\"tags\":[\"Mailing List\"]},{\"url\":\"https://go.dev/issue/77952\",\"source\":\"security@golang.org\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://groups.google.com/g/golang-announce/c/EdhZqrQ98hk\",\"source\":\"security@golang.org\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://pkg.go.dev/vuln/GO-2026-4599\",\"source\":\"security@golang.org\",\"tags\":[\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"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:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-27137\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-10T13:32:09.097820Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-10T13:32:37.164Z\"}}], \"cna\": {\"title\": \"Incorrect enforcement of email constraints in crypto/x509\", \"credits\": [{\"lang\": \"en\", \"value\": \"Jakub Ciolek\"}], \"affected\": [{\"vendor\": \"Go standard library\", \"product\": \"crypto/x509\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.26.0-0\", \"lessThan\": \"1.26.1\", \"versionType\": \"semver\"}], \"packageName\": \"crypto/x509\", \"collectionURL\": \"https://pkg.go.dev\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"newEmailConstraints\"}, {\"name\": \"emailConstraints.query\"}, {\"name\": \"checkConstraints\"}, {\"name\": \"checkChainConstraints\"}, {\"name\": \"parseMailboxes\"}, {\"name\": \"Certificate.Verify\"}]}], \"references\": [{\"url\": \"https://go.dev/cl/752182\"}, {\"url\": \"https://go.dev/issue/77952\"}, {\"url\": \"https://groups.google.com/g/golang-announce/c/EdhZqrQ98hk\"}, {\"url\": \"https://pkg.go.dev/vuln/GO-2026-4599\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"When verifying a certificate chain which contains a certificate containing multiple email address constraints which share common local portions but different domain portions, these constraints will not be properly applied, and only the last constraint will be considered.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"description\": \"CWE-295: Improper Certificate Validation\"}]}], \"providerMetadata\": {\"orgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"shortName\": \"Go\", \"dateUpdated\": \"2026-03-08T05:56:20.771Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-27137\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-03-10T13:32:53.202Z\", \"dateReserved\": \"2026-02-17T19:57:28.434Z\", \"assignerOrgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"datePublished\": \"2026-03-06T21:28:13.748Z\", \"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.