Authentication Bypass in org.keycloak:keycloak-saml-core (CVE-2021-3827)
Summary
Authentication bypass in org.keycloak:keycloak-saml-core (CVE-2021-3827). Confidential information can be exposed externally. Exploitable via Authorization header. Mitigation: upgrade to 18.0.0 or later.
Original description
The description as published by the source.
A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior, an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. The highest threat from this vulnerability is to confidentiality and integrity.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2021-3827 has been found in org.keycloak:keycloak-saml-core.
Attackers can target a specific entry point like Authorization header over the network to misuse the product.
Confidential information can be exposed externally.
What to do: upgrade org.keycloak:keycloak-saml-core to 18.0.0 or later.
If unsure, ask your IT team or search "org.keycloak:keycloak-saml-core CVE-2021-3827" on the vendor's site.
CVE-2021-3827 (org.keycloak:keycloak-saml-core) — CWE-287
Attack vector: remote (network-reachable) / no user interaction
Attack surface: Authorization header
Patched: 18.0.0 — apply immediately
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.
Authentication bypass (CWE-287) exists in org.keycloak:keycloak-saml-core. Attackers reach the vulnerable code path via Authorization header.
Check the vendor advisory for the affected versions of org.keycloak:keycloak-saml-core. Attack surface: Authorization header.
Severity: ?. Confidential information can be exposed externally.
Update to 18.0.0.
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 org.keycloak:keycloak-saml-core 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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2Apply patch patch
Upgrade org.keycloak:keycloak-saml-core to 18.0.0ステージング環境で 18.0.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-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。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory access.redhat.com
- package github.com
- patch github.com
- report bugzilla.redhat.com