https://security-tracker.debian.org/tracker/DSA-6155-1
SPIP 4.0.0 is affected by a Cross Site Request Forgery (CSRF) vulnerability in ecrire/public/aiguiller.php, ecrire/public/balises.php, ecrire/balise/formulaire_.php. To exploit the vulnerability, a visitor must visit a malicious website which redirects to the SPIP website. It is also possible to combine XSS vulnerabilities in SPIP 4.0.0 to exploit it. The vulnerability allows an authenticated attacker to execute malicious code without the knowledge of the user on the website (CSRF).
https://security-tracker.debian.org/tracker/DSA-6174-1
The SPIP template composer/compiler in SPIP 3.1.2 and earlier allows remote authenticated users to execute arbitrary PHP code by uploading an HTML file with a crafted (1) INCLUDE or (2) INCLURE tag and then accessing it with a valider_xml action.