CVE-2026-93998
Description
A flaw was found in the SAML adapter component of Keycloak, which is used to secure applications with SAML-based authentication. The adapter fails to verify that the issuer of a signed SAML assertion matches the expected identity provider configured for the application. If multiple identity providers share the same trusted signing key, an attacker who controls one of those providers can create a validly signed assertion to log into the application as any user, potentially gaining full administrative control.
Statement
The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that exploitation requires the specific condition of a shared signing key between trusted and untrusted issuers. Successful exploitation allows an attacker to bypass authentication and gain unauthorized access, including administrative privileges, to applications protected by the Keycloak SAML adapter. The vulnerability's root cause is the failure to validate the SAML assertion issuer against the configured identity provider entity ID.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.4 | N/A | 7.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control,Integrity,Confidentiality
Technical Impact: Gain Privileges or Assume Identity; Modify Application Data; Execute Unauthorized Code or Commands
An attacker could gain access to sensitive data and possibly execute unauthorized code.
Acknowledgements
Red Hat would like to thank SECTION: Create Trackers yes for reporting this issue.
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