Vulnerability in Build Of Keycloak (CVE-2026-18211)
Summary
Vulnerability in Build Of Keycloak (CVE-2026-18211). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-18211 has been found in Build Of Keycloak.
Risk of unauthorized operations or information disclosure. CVSS score: 4.2/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Build Of Keycloak CVE-2026-18211" on the vendor's site.
CVE-2026-18211 (Build Of Keycloak) — CWE-20 / CVSS v3 4.2
Attack vector: remote (network-reachable) / unauthenticated
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in Build Of Keycloak.
Check the vendor advisory for the affected versions of Build Of Keycloak.
Severity: Medium (CVSS 4.2/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Build Of Keycloak を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- patch secalert@redhat.com
- patch secalert@redhat.com
- web nvd.nist.gov
- web github.com