ruby-saml Remote Denial-of-Service Vulnerability via Compressed SAML Responses

A remote denial-of-service vulnerability has been identified in the ruby-saml library, which provides SAML single sign-on functionality for Ruby applications. This vulnerability affects ruby-saml versions prior to 1.12.4 and 1.13.0 prior to 1.18.0. The issue arises when SAML responses are compressed, allowing an attacker to bypass the message size check. Ruby-saml uses zlib to decompress SAML responses, and the size check is performed before decompression, creating an opportunity for denial-of-service conditions.

Impact

Exploitation of this vulnerability can lead to a remote denial-of-service condition, causing the application to become unresponsive or unavailable.

Remediation

Users are advised to update ruby-saml to version 1.18.0 or 1.12.4. If using omniauth-saml, update the ruby-saml requirement to version 1.18.0.