🛡️ CVE-2026-18211 — build-of-keycloak

🟡 CVSS 4.2 — Medium ✅ No Known Exploit CWE-20 NVD
4.2
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

A flaw was found in the secure-client-uris client policy executor within Keycloak core services. This component is responsible for enforcing security requirements on client configurations, such as requiring encrypted connections for redirect URIs. Due to an improper check that only looks at the start of a web address rather than properly verifying the host, an attacker can bypass these security restrictions by using a specially crafted domain name. This could allow an attacker to intercept sensitive authentication codes over unencrypted connections.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-18211 is classified as CWE-20: Improper Input Validation. The application accepts input without checking that it has the expected form, so malformed values reach code that assumes they are well formed.

Affected software

CVE-2026-18211 is recorded against 1 package.

  • build-of-keycloak

Timeline and source

Published on 31 July 2026 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

access.redhat.com
bugzilla.redhat.com

Details

Severity MEDIUM
CVSS Score 4.2
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
CWE CWE-20
Public Exploit ✅ No
Source NVD
Published 2026-07-31
Updated 2026-08-11
Modified 2026-08-07
Fix URL N/A

Affected Packages

Software From version Fixed in
build-of-keycloak — —

Similar Threats

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