Reflected XSS in Web Proxy Disclaimer Response webpage due proxy URL not been sanitized

Summary

A reflected XSS vulnerability exists in FortiOS web proxy disclaimer response web pages, potentially exploitable by an unauthenticated attacker, via sending a maliciously crafted URL to the victim. The victim visiting the malicious URL would then have arbitrary javascript code executed in the security context of her/his browser.

Affected Products

FortiOS 5.6.0
FortiOS 5.4.0 to 5.4.5
FortiOS 5.2.0 to 5.2.11

Solutions

Upgrade to FortiOS 5.2.12, 5.4.6 or 5.6.1

Acknowledgement

Fortinet is pleased to thank "usd AG" and "Serge Ivanov of Payvision BV" for reporting this vulnerability under responsible disclosure.