Critical severity · published Aug 25, 2026
CVE-2026-16639
Internationalization Single Sign-On - Critical - Access bypass - SA-CONTRIB-2026-081
9.8
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 51% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DR
Drupal · Drupal
0.0.0 before 1.8.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-16639
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-16639
www.drupal.org
https://www.drupal.org/sa-contrib-2026-081
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