Full Report
Drupal security advisory (AV26-308)
Analysis Summary
# Vulnerability: Drupal SAML SSO Service Provider Authentication Bypass
## CVE Details
- **CVE ID:** CVE-2026-XXXXX (Specific ID not provided in the advisory snippet; cross-referenced as SA-CONTRIB-2026-031)
- **CVSS Score:** 9.8 (Estimated - Critical)
- **CWE:** CWE-287 (Improper Authentication)
## Affected Systems
- **Products:** Drupal SAML SSO - Service Provider (Third-party module)
- **Versions:** All versions prior to 3.1.4
- **Configurations:** Systems utilizing this module for Single Sign-On (SSO) authentication via SAML.
## Vulnerability Description
The vulnerability exists within the SAML SSO - Service Provider module's authentication logic. Due to insufficient validation of the SAML assertion response, an unauthenticated remote attacker can bypass the authentication process. This allows the attacker to gain unauthorized access to the Drupal site, potentially with administrative privileges, by spoofing a SAML response.
## Exploitation
- **Status:** PoC availability unknown (Assumed Not Exploited in the wild at time of advisory)
- **Complexity:** Low
- **Attack Vector:** Network
## Impact
- **Confidentiality:** High (Total access to user data and site content)
- **Integrity:** High (Ability to modify site configuration and data)
- **Availability:** High (Potential to lock out legitimate users or delete site data)
## Remediation
### Patches
- **SAML SSO - Service Provider 3.1.4:** Users should upgrade immediately to version 3.1.4 or higher via the standard Drupal module update process.
### Workarounds
- **Disable the Module:** If patching is not immediately possible, navigate to the Extend menu (/admin/modules) and disable the "SAML SSO - Service Provider" module. Note that this will break SSO functionality for all users.
## Detection
- **Indicators of Compromise:** Review Drupal watchdog logs for unusual logins from unexpected IP addresses or logins occurring without corresponding logs in the Identity Provider (IdP) side.
- **Detection Methods:** Audit user accounts for unauthorized changes or the creation of new administrative profiles.
## References
- **Vendor Advisory:** hxxps[://]www[.]drupal[.]org/sa-contrib-2026-031
- **Drupal Security Home:** hxxps[://]www[.]drupal[.]org/security
- **Cyber Centre Advisory:** hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/drupal-security-advisory-av26-308