Vulnerability-Lookup

CVE-2026-18203 (GCVE-0-2026-18203)

Vulnerability from cvelistv5 – Published: 2026-07-31 07:08 – Updated: 2026-07-31 23:20

Title

Keycloak-services: keycloak-services: group policy extendchildren matches sibling group path prefixes

Summary

A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.

Severity

6.5 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-863 - Incorrect Authorization

Assigner

redhat

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-18203	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2508291	issue-trackingx_refsource_REDHAT

Impacted products

4 products

Vendor	Product	Version
Red Hat	Red Hat Build of Keycloak	cpe:/a:redhat:build_keycloak:
Red Hat	Red Hat Data Grid 8	cpe:/a:redhat:jboss_data_grid:8
Red Hat	Red Hat JBoss Enterprise Application Platform Expansion Pack	cpe:/a:redhat:jbosseapxp
Red Hat	Red Hat Single Sign-On 7	cpe:/a:redhat:red_hat_single_sign_on:7

Date Public

2026-07-28 13:44

Credits

Red Hat would like to thank Paul Bottinelli (Trail of Bits) for reporting this issue.

Show details on NVD website

JSON

To clipboard

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GHSA-WX5M-WHR8-48H5

Vulnerability from github – Published: 2026-07-31 09:31 – Updated: 2026-07-31 09:31

Details

Severity

6.5 (Medium)


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

Show details on source website

JSON

To clipboard

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  "affected": [],
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  ],
  "database_specific": {
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    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-31T08:16:27Z",
    "severity": "MODERATE"
  },
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  "id": "GHSA-wx5m-whr8-48h5",
  "modified": "2026-07-31T09:31:18Z",
  "published": "2026-07-31T09:31:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18203"
    },
    {
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      "type": "CVSS_V3"
    }
  ]
}

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.

Action not permitted

CVE-2026-18203 (GCVE-0-2026-18203)

GHSA-WX5M-WHR8-48H5

Tags

Sightings

Nomenclature