Denial of Service in Keycloak Server via Security Headers
A potential Denial of Service (DoS) vulnerability has been identified in Keycloak, which could allow an administrative user with the rights to change realm settings to disrupt the service. This is done by modifying any of the security headers and inserting newlines, which causes the Keycloak server to write to a request that is already terminated, leading to a failure of said request.
Service disruption may happen, users will be unable to access applications relying on Keycloak, or any of the consoles provided by Keycloak itself on the affected realm.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.keycloak:keycloak-quarkus-server | < 26.0.8 | 26.0.8 |
References
- https://github.com/keycloak/keycloak/security/advisories/GHSA-w3g8-r9gw-qrh8
- https://nvd.nist.gov/vuln/detail/CVE-2024-11734
- https://github.com/keycloak/keycloak/commit/93b2a7327b2557eb132a8169086c5e63c81dff79
- https://access.redhat.com/errata/RHSA-2025:0299
- https://access.redhat.com/errata/RHSA-2025:0300
- https://access.redhat.com/security/cve/CVE-2024-11734
- https://bugzilla.redhat.com/show_bug.cgi?id=2328846
- https://github.com/keycloak/keycloak
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-693- Platform
- Java / Kotlin (Maven)
- Package
org.keycloak:keycloak-quarkus-server- Disclosed
- 13.01.2025
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-w3g8-r9gw-qrh8 - CC BY 4.0
Vulnerability history: org.keycloak:keycloak-quarkus-server
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 9
- First → latest
- 11.2024 02.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 6
- Low 2
Disclosures per year
- 2024: 3
- 2025: 4
- 2026: 2
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Denial of Service in Keycloak Server via Security Headers this entry
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