What is the CVSS score of CVE-2026-2603?

CVE-2026-2603 has a CVSS 3.1 base score of 8.1 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.2%.

How to fix or mitigate CVE-2026-2603?

Within 24 hours: Disable SAML IdP-initiated broker login functionality in Keycloak if not operationally critical; audit recent SAML authentication logs for suspicious activity. Within 7 days: Implement network segmentation to restrict Keycloak SAML endpoints to trusted networks only; deploy WAF rules to rate-limit and validate SAML requests; conduct forensic analysis of authentication attempts. Within 30 days: Develop and test a comprehensive identity provider validation framework; monitor vendor communications for patch availability; plan staged remediation once patch is released.

Red Hat Build Of Keycloak 26 4 CVE-2026-2603

EUVD-2026-12690 HIGH

Missing Authentication for Critical Function (CWE-306)

2026-03-18 redhat

GHSA-x4p7-7chp-64hq

Authentication Bypass Red Hat Build Of Keycloak 26 4 Red Hat Build Of Keycloak 26 4 10 Red Hat Build Of Keycloak 26 2 Red Hat Build Of Keycloak 26 2 14 Red Hat

8.1

CVSS 3.1 · Vendor: redhat

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Craft valid SAML response from external IdP
Delivery

Send to Keycloak SAML endpoint
Exploit

Bypass disabled IdP checks
Execution

Complete broker login authentication
Impact

Gain unauthorized access to account

Vulnerability Assessment

Weakness	CWE CWE-306 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication Authentication required for critical functions MITRE ATT&CK 1 technique across 1 tactic: Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Keycloak must have SAML IdP-initiated broker login enabled. Attacker requires valid SAML response from external IdP. Requires low-privilege authenticated access to Keycloak. No victim interaction needed.
Impact	The real-world risk is elevated due to the network-based attack vector (AV:N) and low attack complexity (AC:L), requiring only low privileges (PR:L) and no user interaction (UI:N). The CVSS 8.1 score appropriately reflects high impact to confidentiality and integrity, though availability remains unaffected. While no EPSS score or KEV listing is provided in the data, the vulnerability's technical characteristics suggest moderate exploitation likelihood in environments where disabled SAML IdPs are expected to be fully inactive. The attack requires prior knowledge of valid SAML response formats and an authenticated attacker with low-level access, which somewhat limits the attack surface compared to completely unauthenticated vulnerabilities. Organizations using SAML federation with multiple IdPs where some are temporarily or permanently disabled face the highest risk, as this represents a security control bypass that administrators may rely upon for access restriction. The availability of patches from Red Hat (RHSA-2026:3925, RHSA-2026:3926, RHSA-2026:3947, RHSA-2026:3948) and the specificity of affected versions indicate this is a confirmed, actionable vulnerability requiring prompt remediation rather than theoretical risk.
Exploit ScenarioDerived	An attacker with low-level authenticated access to the network obtains a valid SAML response format from a previously-used or externally-controlled Identity Provider that has been administratively disabled in Keycloak. The attacker crafts and sends this SAML response directly to the Keycloak SAML broker endpoint for IdP-initiated logins, bypassing the disabled state check and successfully authenticating as a user from that IdP. This grants the attacker unauthorized access to applications and resources protected by Keycloak, effectively circumventing administrative security controls intended to revoke access from specific identity sources.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 18, 2026

Keycloak contains an authentication bypass vulnerability in its SAML broker functionality that allows remote attackers with low-level privileges to complete IdP-initiated broker logins even when the SAML Identity Provider has been administratively disabled. Red Hat Build of Keycloak versions 26.2 and 26.4 are affected, with patches available in versions 26.2-16, 26.2.14-1, 26.4-12, and 26.4.10-1. The CVSS score of 8.1 reflects high confidentiality and integrity impact, though no evidence of active exploitation (KEV) or public proof-of-concept has been reported at this time.

RemediationAI

Immediately upgrade to patched versions of Red Hat Build of Keycloak: version 26.2-16 or 26.2.14-1 for the 26.2 series, or version 26.4-12 or 26.4.10-1 for the 26.4 series, as detailed in Red Hat security advisories RHSA-2026:3925, RHSA-2026:3926, RHSA-2026:3947, and RHSA-2026:3948 (see https://access.redhat.com/errata/). Until patching is completed, implement network-level access controls to restrict the Keycloak SAML endpoint to trusted IP ranges only, audit all SAML IdP configurations to verify enabled/disabled states match security policies, and monitor authentication logs for unexpected IdP-initiated logins from disabled providers. As an additional interim control, consider removing or invalidating SAML metadata for disabled IdPs from the Keycloak configuration to prevent acceptance of assertions from those sources. Review all recent authentication events to identify potential exploitation attempts where disabled IdPs successfully authenticated users.

Affected VersionsENISA

Red Hat build of Keycloak 26.4 patch: 26.4-12

Red Hat build of Keycloak 26.4 patch: 26.4.10-1

Red Hat build of Keycloak 26.2 patch: 26.2.14-1

Red Hat build of Keycloak 26.2 patch: 26.2-16

Affected Packages

maven org.keycloak:keycloak-server-spi-private fix: 26.5.5

maven org.keycloak:keycloak-services fix: 26.5.5

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in maven

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability affects the SAML (Security Assertion Markup Language) broker implementation in Keycloak, Red Hat's open-source identity and access management solution. The flaw stems from CWE-306 (Missing Authentication for Critical Function), where the SAML endpoint processing IdP-initiated broker logins fails to properly validate whether the configured Identity Provider is enabled before accepting authentication assertions. Affected products include Red Hat Build of Keycloak 26.2 (CPE: cpe:2.3:a:red_hat:red_hat_build_of_keycloak_26.2) and 26.4 (CPE: cpe:2.3:a:red_hat:red_hat_build_of_keycloak_26.4). The vulnerability exists in the broker login flow where external IdPs send SAML responses to Keycloak's SAML endpoint, and the system processes these responses without checking the administrative state of the IdP configuration.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (redhat) PRIMARY 8.1 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Red Hat 8.1 HIGH

Primary rating from Vendor (redhat).

CVSS VectorVendor: redhat

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Patch released

Apr 10, 2026 - 08:30 nvd

Patch available

CVE Published

Mar 18, 2026 - 01:14 nvd

HIGH 8.1

DescriptionCVE.org

A flaw was found in Keycloak. A remote attacker could bypass security controls by sending a valid SAML response from an external Identity Provider (IdP) to the Keycloak SAML endpoint for IdP-initiated broker logins. This allows the attacker to complete broker logins even when the SAML Identity Provider is disabled, leading to unauthorized authentication.

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

53 maven packages depend on org.keycloak:keycloak-server-spi-private (22 direct, 31 indirect)
43 maven packages depend on org.keycloak:keycloak-services (15 direct, 28 indirect)

Ecosystem-wide dependent count for version 26.5.5 and other introduced versions.

Executive ViewAI

Why It Matters

Keycloak's SAML authentication endpoint contains a critical flaw that allows attackers to bypass identity provider controls and gain unauthorized access to systems, even when those providers are disabled. Organizations relying on Keycloak for federated identity management face immediate risk of unauthorized user authentication and potential lateral movement into protected resources.

Business Impact: High

Compensating Controls

Disable SAML IdP-initiated broker login feature if operationally feasible; implement Web Application Firewall (WAF) rules to validate SAML response signatures and reject responses from disabled IdPs; restrict network access to Keycloak SAML endpoints via firewall segmentation; enforce strict rate limiting on authentication endpoints; implement enhanced logging and alerting for SAML authentication failures; conduct manual validation of external IdP provider status before accepting SAML responses at application layer if possible.

Threat Intelligence Overview

EPSS Score

0.2%

Top 62% exploitable

Threat Intel

1 source

Data Quality

6 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS GHSA Vendor

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.2%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.