Skip to content
Fencer Intel
medium 5.3

CVE-2026-2575 json

Keycloak: keycloak: denial of service due to excessive samlrequest decompression

published 2026-03-18 7 mo ago modified 2026-10-07 33 d ago also BIT-keycloak-2026-2575 , EUVD-2026-12766 , GHSA-xv6h-r36f-3gp5

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 51%
public exploits
0
none known

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.

Patch / fix

  • maven org.keycloak:keycloak-saml-adapter-core 26.5.4
  • maven org.keycloak:keycloak-saml-core 26.5.4
  • maven org.keycloak:keycloak-services 26.5.4
  • bitnami keycloak 26.4.10
  • Red Hat Red Hat build of Keycloak 26.4 26.4-12, 26.4.10-1
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 7 0:18.0.20-1.redhat_00001.1.el7sso
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 8 0:18.0.20-1.redhat_00001.1.el8sso
  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 9 0:18.0.20-1.redhat_00001.1.el9sso
  • Red Hat RHEL-8 based Middleware Containers 7.6-85
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el9sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el9sso
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el7sso

red hat advisories RHSA-2026:76129RHSA-2026:76130RHSA-2026:76128

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-2575 updated cvss 5.3

keycloak: Keycloak: Denial of Service due to excessive SAMLRequest decompression

  • Red Hat Middleware Containers for OpenShift rh-sso-7/sso76-openshift-rhel8 7.6-85
    fixed: vendor fix RHSA-2026:76134
  • Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-12, rhbk/keycloak-rhel9-operator 26.4-12, rhbk/keycloak-operator-bundle 26.4.10-1
    fixed: vendor fix RHSA-2026:3948
  • Red Hat build of Keycloak 26.4.10
    fixed: vendor fix RHSA-2026:3947
  • Red Hat Single Sign-On 7.6 for RHEL 7 Server rh-sso7-keycloak 18.0.20-1.redhat_00001.1.el7sso, rh-sso7-keycloak-server 18.0.20-1.redhat_00001.1.el7sso
    fixed: vendor fix RHSA-2026:76128
  • Red Hat Single Sign-On 7.6 for RHEL 8 rh-sso7-keycloak 18.0.20-1.redhat_00001.1.el8sso, rh-sso7-keycloak-server 18.0.20-1.redhat_00001.1.el8sso
    fixed: vendor fix RHSA-2026:76129
  • Red Hat Single Sign-On 7.6 for RHEL 9 rh-sso7-keycloak 18.0.20-1.redhat_00001.1.el9sso, rh-sso7-keycloak-server 18.0.20-1.redhat_00001.1.el9sso
    fixed: vendor fix RHSA-2026:76130
  • Red Hat Single Sign-On 7.6.13
    fixed: vendor fix RHSA-2026:76132

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.66% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
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
bitnami keycloak
>=26.4.0, <26.4.10
26.4.10

Affected products

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

Classification

Weakness
  • CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.