Vulnerability-Lookup

GHSA-C8XX-FR3X-6M5W

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

Details

A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect (OIDC) authentication flows. The issue occurs because the security check designed to prevent HTTP parameter pollution only inspects the query portion of a redirect URL and ignores the fragment portion. When a client is configured with a wildcard redirect URI, an attacker can use this to inject duplicate security parameters into the login response. If a client application is not configured correctly, it might trust the attacker's injected data instead of the real security information from Keycloak, leading to session fixation or account confusion.

Severity

3.4 (Low)


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

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  "aliases": [
    "CVE-2026-18209"
  ],
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    "cwe_ids": [
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    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-31T08:16:27Z",
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  "id": "GHSA-c8xx-fr3x-6m5w",
  "modified": "2026-07-31T09:31:18Z",
  "published": "2026-07-31T09:31:18Z",
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    },
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    },
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      "type": "CVSS_V3"
    }
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}

CVE-2026-18209 (GCVE-0-2026-18209)

Vulnerability from cvelistv5 – Published: 2026-07-31 07:08 – Updated: 2026-07-31 15:58

Title

Keycloak-services: keycloak-services: oidc redirect_uri fragment bypass in http parameter pollution check

Summary

Severity

3.4 (Low)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-1288 - Improper Validation of Consistency within Input

Assigner

redhat

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-18209	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2508305	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 13:13

Credits

Red Hat would like to thank default-cybe for reporting this issue.

Show details on NVD website

JSON

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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.

Action not permitted

GHSA-C8XX-FR3X-6M5W

CVE-2026-18209 (GCVE-0-2026-18209)

Tags

Sightings

Nomenclature