CVE-2026-16639 Internationalization Single Sign-On - Critical - Access bypass - SA-CONTRIB-2026-081
Attackers can bypass authentication in the Drupal Internationalization Single Sign-On module, potentially gaining unauthorized access to user accounts.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-16639?
CVE-2026-16639 is a critical authentication bypass vulnerability in Drupal Internationalization Single Sign-On, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Authentication Bypass Using an Alternate Path or Channel vulnerability in Drupal Internationalization Single Sign-On allows Authentication Bypass. This issue affects Internationalization Single Sign-On versions: from 0.0.0 to 1.8.0.
Weakness: CWE-288
Which versions are affected by CVE-2026-16639?
Linux distribution packages (1)
drupal/i18n_sso Packagist:https://packages.drupal.org/8 | All versions | 1.8.0 |
How do I fix CVE-2026-16639?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-16639 being exploited?
There is no known exploitation of CVE-2026-16639 in the wild and no public exploit code.
Sources
Also known as DRUPAL-CONTRIB-2026-081, GHSA-p748-p4j4-gpx6.