Znuny

In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable "Remote-User" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials.

Published: 2026-10-15T03:43:10.406Z
Updated: 2026-10-19T18:42:25.087Z

In Znuny LTS before 6.5.21 and Znuny before 7.3.3, there is reflected XSS in AdminCommunicationLog (aka the communication log administration view).

Published: 2026-06-05T01:57:34.843Z
Updated: 2026-06-05T18:21:36.439Z

In Znuny LTS before 6.5.21 and Znuny before 7.3.3, XSS can occur via stored user preferences.

Published: 2026-06-05T01:52:00.386Z
Updated: 2026-06-05T18:23:01.633Z