CVE-2026-2575 Keycloak: keycloak: denial of service due to excessive samlrequest decompression
An unauthenticated attacker can cause a denial of service in Keycloak by sending a highly compressed SAMLRequest that triggers an OutOfMemoryError.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-2575?
CVE-2026-2575 is a medium-severity denial of service vulnerability in Redhat Build of Keycloak, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-409
Which versions are affected by CVE-2026-2575?
7 open source packages ship an affected version, including org.keycloak:keycloak-saml-adapter-core, keycloak and org.keycloak:keycloak-saml-core. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.keycloak:keycloak-saml-adapter-core Maven | All versions | 26.5.4 |
org.keycloak:keycloak-saml-adapter-core Maven | All versions | 26.5.4 |
keycloak Bitnami | From 26.4.0 | 26.4.10 |
org.keycloak:keycloak-saml-core Maven | All versions | 26.5.4 |
org.keycloak:keycloak-saml-core Maven | All versions | 26.5.4 |
org.keycloak:keycloak-services Maven | All versions | 26.5.4 |
1 more packages
org.keycloak:keycloak-services Maven | All versions | 26.5.4 |
Products include Redhat Build of Keycloak.
How do I fix CVE-2026-2575?
Upgrade org.keycloak:keycloak-saml-adapter-core to 26.5.4 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-2575 being exploited?
There is no known exploitation of CVE-2026-2575 in the wild and no public exploit code.
Other vulnerabilities in Redhat Build of Keycloak
- CVE-2026-15572 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
- CVE-2026-3047 Keycloak SAML Broken has Authentication Bypass by Primary Weakness
- CVE-2026-15573 Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher
- CVE-2026-16102 Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers
- CVE-2026-1609 Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users
Sources
Also known as BIT-keycloak-2026-2575, ECHO-12de-2dca-d7dc, GHSA-xv6h-r36f-3gp5, MINI-7f5h-wq4f-m4j2, MINI-v7vj-pgq3-jxp9.