Description

A user with access to a valid SAML response may impersonate another user under specific conditions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-08-12T15:18:22.477Z",
  "pubdate": "2026-08-12T15:18:22.477Z",
  "executiveSummary": "This vulnerability involves an improper validation flaw within Security Assertion Markup Language (SAML) response processing, which allows an authenticated user to successfully impersonate arbitrary users under specific operational conditions. The security impact is severe, leading to potential privilege escalation, unauthorized data access, and compromise of system integrity across affected identity federation systems.\nThe vulnerability affects systems relying on SAML-based single sign-on (SSO) implementations that fail to adequately verify assertion ownership, recipient constraints, or cryptographic signatures against the intended session context. An attacker requires valid, lower-privileged access to the system to initiate the attack flow.\nRisk implications include full account takeover within the security domain, unauthorized execution of administrative functions, and regulatory compliance violations due to broken access controls and non-repudiation failures.\nExploitation prerequisites include possession of a valid SAML response and the presence of logic flaws in the assertion parsing or mapping engine. The attacker leverages these conditions to manipulate assertion attributes or replay valid assertions in unauthorized contexts to assume the security context of targeted victims without knowing their credentials.",
  "technicalDetails": "The root cause of this vulnerability lies in the insecure handling and validation of SAML assertions within the authentication pipeline, specifically regarding the binding of the assertion to the authenticated session or the insufficient validation of the Subject NameID and assertion attributes.\nDuring the assertion consumption phase, the vulnerable component fails to strictly verify whether the recipient of the SAML response matches the authenticated entity presenting it, or it improperly processes assertion attributes that dictate the user identity mapping within the local application context.\nThe step-by-step attack flow proceeds as follows: First, the attacker obtains a legitimate SAML response through standard authentication mechanisms or interception under specific conditions. Second, the attacker interacts with the service provider (SP) authentication endpoint. Third, by exploiting the validation logic flaw, the attacker injects or presents the SAML response in a manner that bypasses assertion-to-session binding checks. Fourth, the application processes the assertion and maps the session to the Subject specified within the SAML payload rather than the authenticated channel context, resulting in successful privilege escalation and identity spoofing.\nAuthentication requirements dictate that the attacker must possess valid credentials to obtain an initial authentic SAML response. Privilege requirements are low, as a standard user with valid access can trigger the vulnerability. Network exposure is typically external, affecting any web-based application exposing a SAML assertion consumer service (ACS) endpoint with flawed validation logic.\nPost-exploitation impact includes unauthorized horizontal or vertical movement, data exfiltration, manipulation of victim resources, and persistent unauthorized access within the affected federated environment."
}