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 products
redhat: build of keycloak
References9
- access.redhat.com/errata/RHSA-2026:3947 Vendor Advisory
- access.redhat.com/errata/RHSA-2026:3948 Vendor Advisory
- access.redhat.com/security/cve/CVE-2026-2575 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2440149 Issue TrackingVendor Advisory
- access.redhat.com/errata/RHSA-2026:76128
- access.redhat.com/errata/RHSA-2026:76129
- access.redhat.com/errata/RHSA-2026:76130
- access.redhat.com/errata/RHSA-2026:76132
- access.redhat.com/errata/RHSA-2026:76134
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS — exploit probability
- 1% percentile: 52 · as of 12 November 2026
- CWE
- CWE-409
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.