CVE-2026-9084 (GCVE-0-2026-9084)

Vulnerability from cvelistv5 – Published: 2026-05-20 14:22 – Updated: 2026-05-20 15:28
VLAI
Title
MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations
Summary
MISP’s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim’s email address and authenticate as that user, leading to account takeover.
Severity
6 (Medium)
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-287 - Improper Authentication
Assigner
References
Impacted products
Vendor Product Version
misp misp Affected: 2.5.0 , ≤ 2.5.37 (semver)
Create a notification for this product.
Credits
Ali Ganiyev Luciano Righetti
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-9084",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-20T15:28:48.726589Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-20T15:28:55.640Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "misp",
          "vendor": "misp",
          "versions": [
            {
              "lessThanOrEqual": "2.5.37",
              "status": "affected",
              "version": "2.5.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Ali Ganiyev"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Luciano Righetti"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "MISP\u2019s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the \u003ccode\u003eemail\u003c/code\u003e claim when the local account had no stored \u003ccode\u003esub\u003c/code\u003e value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim\u2019s email address and authenticate as that user, leading to account takeover.\u003cbr\u003e"
            }
          ],
          "value": "MISP\u2019s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim\u2019s email address and authenticate as that user, leading to account takeover."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-115",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-115 Authentication Bypass"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "ADJACENT",
            "baseScore": 6,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-287",
              "description": "CWE-287 Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-20T14:22:59.019Z",
        "orgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
        "shortName": "CIRCL"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/MISP/MISP/commit/71f5662c1b5886613d2cd5c72fd93bb4ca6fa172"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
    "assignerShortName": "CIRCL",
    "cveId": "CVE-2026-9084",
    "datePublished": "2026-05-20T14:22:59.019Z",
    "dateReserved": "2026-05-20T14:21:56.589Z",
    "dateUpdated": "2026-05-20T15:28:55.640Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-9084",
      "date": "2026-07-30",
      "epss": "0.00182",
      "percentile": "0.08087"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-9084\",\"sourceIdentifier\":\"5a6e4751-2f3f-4070-9419-94fb35b644e8\",\"published\":\"2026-05-20T16:16:28.107\",\"lastModified\":\"2026-07-23T12:10:00.110\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"MISP\u2019s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim\u2019s email address and authenticate as that user, leading to account takeover.\"},{\"lang\":\"es\",\"value\":\"El plugin de autenticaci\u00f3n OIDC de MISP permit\u00eda el enlace autom\u00e1tico de una identidad OIDC a una cuenta de usuario local existente bas\u00e1ndose en la reclamaci\u00f3n de correo electr\u00f3nico cuando la cuenta local no ten\u00eda un valor \u0027sub\u0027 almacenado. Bajo configuraciones de IdP inseguras o no confiables donde la propiedad del correo electr\u00f3nico no se exige, un atacante con un token OIDC v\u00e1lido podr\u00eda afirmar la direcci\u00f3n de correo electr\u00f3nico de una v\u00edctima y autenticarse como ese usuario, lo que llevar\u00eda a una toma de control de la cuenta.\"}],\"affected\":[{\"source\":\"5a6e4751-2f3f-4070-9419-94fb35b644e8\",\"affectedData\":[{\"vendor\":\"misp\",\"product\":\"misp\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"2.5.0\",\"lessThanOrEqual\":\"2.5.37\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"5a6e4751-2f3f-4070-9419-94fb35b644e8\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/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\",\"baseScore\":6.0,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"ADJACENT\",\"attackComplexity\":\"HIGH\",\"attackRequirements\":\"PRESENT\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"HIGH\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-05-20T15:28:48.726589Z\",\"id\":\"CVE-2026-9084\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"5a6e4751-2f3f-4070-9419-94fb35b644e8\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-287\"}]}],\"references\":[{\"url\":\"https://github.com/MISP/MISP/commit/71f5662c1b5886613d2cd5c72fd93bb4ca6fa172\",\"source\":\"5a6e4751-2f3f-4070-9419-94fb35b644e8\"}]}}",
    "redhat_vex": {
      "current_release_date": "2026-06-05T19:33:58+00:00",
      "cve": "CVE-2026-9084",
      "id": "CVE-2026-9084",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9084.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-9084\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-20T15:28:48.726589Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-20T15:28:52.979Z\"}}], \"cna\": {\"title\": \"MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations\", \"source\": {\"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"Ali Ganiyev\"}, {\"lang\": \"en\", \"type\": \"remediation developer\", \"value\": \"Luciano Righetti\"}], \"impacts\": [{\"capecId\": \"CAPEC-115\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"CAPEC-115 Authentication Bypass\"}]}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV4_0\": {\"Safety\": \"NOT_DEFINED\", \"version\": \"4.0\", \"Recovery\": \"NOT_DEFINED\", \"baseScore\": 6, \"Automatable\": \"NOT_DEFINED\", \"attackVector\": \"ADJACENT\", \"baseSeverity\": \"MEDIUM\", \"valueDensity\": \"NOT_DEFINED\", \"vectorString\": \"CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N\", \"exploitMaturity\": \"NOT_DEFINED\", \"providerUrgency\": \"NOT_DEFINED\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"NONE\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"HIGH\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"misp\", \"product\": \"misp\", \"versions\": [{\"status\": \"affected\", \"version\": \"2.5.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"2.5.37\"}], \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://github.com/MISP/MISP/commit/71f5662c1b5886613d2cd5c72fd93bb4ca6fa172\", \"tags\": [\"patch\"]}], \"x_generator\": {\"engine\": \"Vulnogram 0.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"MISP\\u2019s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim\\u2019s email address and authenticate as that user, leading to account takeover.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"MISP\\u2019s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the \u003ccode\u003eemail\u003c/code\u003e claim when the local account had no stored \u003ccode\u003esub\u003c/code\u003e value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim\\u2019s email address and authenticate as that user, leading to account takeover.\u003cbr\u003e\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-287\", \"description\": \"CWE-287 Improper Authentication\"}]}], \"providerMetadata\": {\"orgId\": \"5a6e4751-2f3f-4070-9419-94fb35b644e8\", \"shortName\": \"CIRCL\", \"dateUpdated\": \"2026-05-20T14:22:59.019Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-9084\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-20T15:28:55.640Z\", \"dateReserved\": \"2026-05-20T14:21:56.589Z\", \"assignerOrgId\": \"5a6e4751-2f3f-4070-9419-94fb35b644e8\", \"datePublished\": \"2026-05-20T14:22:59.019Z\", \"assignerShortName\": \"CIRCL\"}",
      "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.