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Vulnerability · Published Mar 18, 2026 · Assigned by redhat

CVE-2026-2575Keycloak: keycloak: denial of service due to excessive samlrequest decompression

Medium 5.3

In plain English

A medium-severity security flaw in Red Hat build of Keycloak 26.4 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.7%top 48.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Mavenorg.keycloak:keycloak-saml-adapter-core26.5.4GHSA-xv6h-r36f-3gp5
Mavenorg.keycloak:keycloak-saml-core26.5.4GHSA-xv6h-r36f-3gp5
Mavenorg.keycloak:keycloak-services26.5.4GHSA-xv6h-r36f-3gp5

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4 see references
Red Hat Red Hat build of Keycloak 26.4.10 see references
Red Hat Red Hat Single Sign-On 7.6.13 see references
Red Hat Red Hat Single Sign-On 7.6 for RHEL 7 see references
Red Hat Red Hat Single Sign-On 7.6 for RHEL 8 see references
Red Hat Red Hat Single Sign-On 7.6 for RHEL 9 see references
Red Hat RHEL-8 based Middleware Containers see references

Weakness: CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References