CoSign Single Signon vulnerability

The CoSign Single Signon plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the `$_SERVER['PHP_SELF']` parameter in all versions up to, and including, 0.3.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

Published 5 Dec 2025Updated 18 Oct 20263 sources
CVSS 6.1

What happened

The CoSign Single Signon plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the `$_SERVER['PHP_SELF']` parameter in all versions up to, and including, 0.3.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

Affected versions

CoSign Single Signon: 0 through 0.3.1 (semver) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.