Disclosure summary
A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
GitHub Reviewed Security Advisories · GHSA-xv6h-r36f-3gp5
Open original source · Updated Oct 06, 2026
Keycloak: Denial of Service due to excessive SAMLRequest decompression
Source severity: MEDIUM / 0
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| maven | org.keycloak:keycloak-saml-adapter-core | < 26.5.4 | 26.5.4 |
| maven | org.keycloak:keycloak-saml-core | < 26.5.4 | 26.5.4 |
| maven | org.keycloak:keycloak-services | < 26.5.4 | 26.5.4 |
Original records & references
- NIST NVD record
- CVE Program record
- github.com — Reviewed advisory
PUBLISHED 2026-03-18T02:31:20-04:00
MODIFIED 2026-10-06T08:31:28-04:00
INGESTED 2026-10-06T11:45:43-04:00