---
id: CVE-2026-4874
title: A flaw was found in Keycloak
summary: >-
  A flaw was found in Keycloak. An authenticated attacker can perform
  Server-Side Request Forgery (SSRF) by manipulating the `client_session_host`
  parameter during refresh token requests. This occurs when a Keycloak client is
  configured to…
severity: low
cvss: 3.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-918
published: '2026-03-26'
updated: '2026-06-26'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-4874'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:25097'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:25098'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:30049'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:30050'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-4874'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2451611'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00295
epssPercentile: 0.2243
ingestedAt: '2026-06-26T16:43:13.621Z'
---

## Overview

A flaw was found in Keycloak. An authenticated attacker can perform Server-Side Request Forgery (SSRF) by manipulating the `client_session_host` parameter during refresh token requests. This occurs when a Keycloak client is configured to use the `backchannel.logout.url` with the `application.session.host` placeholder. Successful exploitation allows the attacker to make HTTP requests from the Keycloak server’s network context, potentially probing internal networks or internal APIs, leading to information disclosure.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.