Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-4634— Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters

CVSS 7.5 · High EPSS 0.52% · P41

Possible ATT&CK Techniques 1AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 8

VendorProductVersion RangeStatus
Red HatRed Hat build of Keycloak 26.226.2.15-1< *unaffected
26.2-18< *unaffected
26.2-18< *unaffected
Red HatRed Hat build of Keycloak 26.2.15anyunaffected
Red HatRed Hat build of Keycloak 26.426.4.11-1< *unaffected
26.4-14< *unaffected
26.4-14< *unaffected
Red HatRed Hat build of Keycloak 26.4.11anyunaffected
Get alerts for future matching vulnerabilitiesLog in to subscribe

I. Basic Information for CVE-2026-4634

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters
Source: NVD (National Vulnerability Database)
Vulnerability Description
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
循环内过多的平台资源消耗
Source: NVD (National Vulnerability Database)
Vulnerability Title
Keycloak 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Keycloak是Keycloak开源的一种开源身份和访问管理解决方案。 Keycloak存在安全漏洞，该漏洞源于向OIDC令牌端点发送特制的超长scope参数POST请求，可能导致资源消耗过高和处理时间延长，最终造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
Red HatRed Hat build of Keycloak 26.2 26.2.15-1 ~ * cpe:/a:redhat:build_keycloak:26.2::el9
Red HatRed Hat build of Keycloak 26.2 26.2-18 ~ * cpe:/a:redhat:build_keycloak:26.2::el9
Red HatRed Hat build of Keycloak 26.2 26.2-18 ~ * cpe:/a:redhat:build_keycloak:26.2::el9
Red HatRed Hat build of Keycloak 26.2.15-cpe:/a:redhat:build_keycloak:26.2::el9
Red HatRed Hat build of Keycloak 26.4 26.4.11-1 ~ * cpe:/a:redhat:build_keycloak:26.4::el9
Red HatRed Hat build of Keycloak 26.4 26.4-14 ~ * cpe:/a:redhat:build_keycloak:26.4::el9
Red HatRed Hat build of Keycloak 26.4 26.4-14 ~ * cpe:/a:redhat:build_keycloak:26.4::el9
Red HatRed Hat build of Keycloak 26.4.11-cpe:/a:redhat:build_keycloak:26.4::el9

II. Public POCs for CVE-2026-4634

#POC DescriptionSource LinkShenlong Link
AI-Generated POCPremium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-4634

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-4634 (6)

Same Patch Batch · Red Hat · 2026-04-02 · 5 CVEs total

CVE-2026-46368.1 HIGHKeycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized acce
CVE-2026-42827.4 HIGHKeycloak: keycloak: privilege escalation via forged authorization codes due to singleuseob
CVE-2026-38727.3 HIGHKeycloak: keycloak: information disclosure due to redirect_uri validation bypass
CVE-2026-43255.3 MEDIUMKeycloak: keycloak: replay of action tokens via improper handling of single-use entries

IV. Related Vulnerabilities

Same product: Red Hat build of Keycloak 26.2
Same vendor: Red Hat
Same weakness: CWE-1050

V. Comments for CVE-2026-4634

No comments yet

Leave a comment