Keycloak: Denial of Service via specially crafted SAML input
A flaw was found in Keycloak. A remote, unauthenticated attacker can send a specially crafted XML input to the Security Assertion Markup Language (SAML) endpoint. This malicious input can cause high CPU usage and worker thread starvation, leading to a Denial of Service (DoS) where the server becomes unavailable.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.keycloak:keycloak-saml-core | < 26.6.2 | 26.6.2 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-7307
- https://github.com/keycloak/keycloak/pull/49119
- https://github.com/keycloak/keycloak/commit/be84d28ce4c69c038d542f11405d5ede1d61f4a9
- https://access.redhat.com/errata/RHSA-2026:19594
- https://access.redhat.com/errata/RHSA-2026:19595
- https://access.redhat.com/errata/RHSA-2026:19596
- https://access.redhat.com/errata/RHSA-2026:19597
- https://access.redhat.com/security/cve/CVE-2026-7307
- https://bugzilla.redhat.com/show_bug.cgi?id=2476526
- https://github.com/keycloak/keycloak
- https://github.com/keycloak/keycloak/releases/tag/26.6.2
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-1286- Platform
- Java / Kotlin (Maven)
- Package
org.keycloak:keycloak-saml-core- Disclosed
- 19.05.2026
- Updated
- 11.10.2026 12:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-p5mv-gj8j-xqgf - CC BY 4.0
Vulnerability history: org.keycloak:keycloak-saml-core
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
- 4
- First → latest
- 04.2022 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 3
- Medium 1
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 2
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Keycloak: Denial of Service via specially crafted SAML input this entry
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