Executive brief
Cotonti Siena, a content management system, is vulnerable to an attack that allows unauthorized individuals to change website settings. By tricking a logged-in administrator into visiting a malicious link, an attacker can disable security filters and upload harmful files. This can lead to a complete takeover of the website, allowing attackers to steal data or disrupt operations.
Technical details
A Cross-Site Request Forgery (CSRF) vulnerability exists in Cotonti Siena versions 0.9.26 and earlier due to a lack of CSRF token validation in the 'admin.php' configuration update handler and the PFS module upload handler. An unauthenticated attacker can exploit this by tricking an authenticated administrator into submitting a forged POST request. This allows the attacker to modify system configurations, such as disabling the file extension blocklist (setting 'pfsfilecheck' to 0). Once the security filters are disabled, the attacker can use a second CSRF request to upload a malicious PHP script via the Personal File Space (PFS) module, resulting in remote code execution (RCE). As of the disclosure date, no official patch has been released by the vendor.
Affected products
- Cotonti Siena <= 0.9.26
Timeline
- 2026-06-06: other: Vulnerability discovered by researcher Saidakbarxon Maxsudxonov
- 2026-06-17: other: Initial disclosure to Cotonti maintainers via GitHub Security Advisory
- 2026-07-09: advisory: Public disclosure and CVE assignment by VulnCheck