SPIP < 4.4.9 Stored Cross-Site Scripting via Syndicated Sites

SPIP before 4.4.9 allows Stored Cross-Site Scripting (XSS) via syndicated sites in the private area. The #URL_SYNDIC output is not properly sanitized on the private syndicated site page, allowing an attacker who can set a malicious syndication URL to inject persistent scripts that execute when other administrators view the syndicated site details.