Vulnerability-Lookup

GHSA-M6QJ-3MPP-57V8

Vulnerability from github – Published: 2026-05-20 18:31 – Updated: 2026-06-26 09:30

Summary

Keycloak: Insufficient verification proof scoping enables identity provider account linking attack and account compromise

Details

A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.

Severity

6.4 (Medium)


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

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.keycloak:keycloak-services"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.6.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-9087"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-11T16:40:55Z",
    "nvd_published_at": "2026-05-20T17:16:32Z",
    "severity": "MODERATE"
  },
  "details": "A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId,\nidpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim\u0027s local account.",
  "id": "GHSA-m6qj-3mpp-57v8",
  "modified": "2026-06-26T09:30:45Z",
  "published": "2026-05-20T18:31:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9087"
    },
    {
      "type": "WEB",
      "url": "https://github.com/keycloak/keycloak/commit/37dabf59d0b5ca3e5b3b272bcd3b2580e67b94dd"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:25097"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:25098"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:30049"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:30050"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-9087"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480172"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/keycloak/keycloak"
    },
    {
      "type": "WEB",
      "url": "https://github.com/keycloak/keycloak/releases/tag/26.6.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Keycloak: Insufficient verification proof scoping enables identity provider account linking attack and account compromise"
}

CVE-2026-9087 (GCVE-0-2026-9087)

Vulnerability from cvelistv5 – Published: 2026-05-20 16:13 – Updated: 2026-08-03 10:41

Title

Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login

Summary

Severity

6.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-21 14:01 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key

Assigner

redhat redhat root

References

6 references

URL	Tags
https://access.redhat.com/errata/RHSA-2026:25097	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:25098	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:30049	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:30050	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-9087	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2480172	issue-trackingx_refsource_REDHAT

Impacted products

6 products

Vendor	Product	Version
Red Hat	Red Hat build of Keycloak 26.4	Unaffected: 26.4.13-1 , < * (rpm) cpe:/a:redhat:build_keycloak:26.4::el9
Red Hat	Red Hat build of Keycloak 26.4	Unaffected: 26.4-19 , < * (rpm) cpe:/a:redhat:build_keycloak:26.4::el9
Red Hat	Red Hat build of Keycloak 26.4.13	cpe:/a:redhat:build_keycloak:26.4::el9
Red Hat	Red Hat build of Keycloak 26.6	Unaffected: 26.6.3-3 , < * (rpm) cpe:/a:redhat:build_keycloak:26.6::el9
Red Hat	Red Hat build of Keycloak 26.6	Unaffected: 26.6-6 , < * (rpm) cpe:/a:redhat:build_keycloak:26.6::el9
Red Hat	Red Hat build of Keycloak 26.6.3	cpe:/a:redhat:build_keycloak:26.6::el9

Date Public

2026-05-20 14:53

Credits

Red Hat would like to thank Emilio Galle for reporting this issue.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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        "metrics": [
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                  },
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                  }
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                "timestamp": "2026-05-21T14:01:27.979329Z",
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        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:build_keycloak:26.6::el9"
          ],
          "defaultStatus": "unaffected",
          "packageName": "rhbk/keycloak-rhel9",
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      ],
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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.