---
id: CVE-2026-7307
title: A flaw was found in Keycloak
summary: >-
  A flaw was found in Keycloak. A remote, unauthenticated attacker can send a
  specially crafted XML input to the Security Assertion Markup Language (SAML)
  endpoint. This malicious input can cause high CPU usage and worker thread
  starvation…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-1286
vendor: redhat
product: build_of_keycloak
affected:
  - 'build_of_keycloak >= 26.4, < 26.4.12'
patched:
  - build_of_keycloak 26.4.12
published: '2026-05-19'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T17:17:26.963'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-7307'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:19594'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:19595'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:19596'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:19597'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:76128'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:76129'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:76130'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:76132'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:76134'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-7307'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2476526'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:19594'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19595'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19596'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19597'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-7307'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2476526'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-7307.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-7307'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-7307'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00878
epssPercentile: 0.58861
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-05-19T12:49:06.304635Z'
ingestedAt: '2026-09-29T16:39:33.225Z'
---

## Overview

A flaw was found in Keycloak. A remote, unauthenticated attacker can send a specially crafted XML input to the Security Assertion Markup Language (SAML) endpoint. This malicious input can cause high CPU usage and worker thread starvation, leading to a Denial of Service (DoS) where the server becomes unavailable.

## Affected

- `build_of_keycloak >= 26.4, < 26.4.12`

## Remediation

Upgrade past the affected range:

- `build_of_keycloak 26.4.12`

## Vendor advisories

- **RHSA-2026:76134** · Red Hat · fixed in: Middleware Containers for OpenShift · released 2026-10-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:76134)
- **RHSA-2026:19595** · Red Hat · fixed in: Red Hat build of Keycloak 26.2 · released 2026-05-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:19595)
- **RHSA-2026:19597** · Red Hat · fixed in: Red Hat build of Keycloak 26.4 · released 2026-05-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:19597)
- **RHSA-2026:76132** · Red Hat · fixed in: Red Hat Single Sign-On 7.6.13 · released 2026-10-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:76132)
- **RHSA-2026:19594** · Red Hat · fixed in: Red Hat build of Keycloak 26.2.16 · released 2026-05-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:19594)
- **RHSA-2026:19596** · Red Hat · fixed in: Red Hat build of Keycloak 26.4.12 · released 2026-05-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:19596)