SPIP before 3.1.11 and 3.2 before 3.2.5 allows prive/formulaires/login.php XSS via error messages.
https://www.debian.org/security/2019/dsa-4532
https://usn.ubuntu.com/4536-1/
https://seclists.org/bugtraq/2019/Sep/40
https://lists.debian.org/debian-lts-announce/2019/10/msg00038.html
https://git.spip.net/SPIP/spip/commit/3c12a82c7d9d4afd09e708748fa82e7836174028
https://blog.spip.net/Mise-a-jour-CRITIQUE-de-securite-Sortie-de-SPIP-3-2-5-et-SPIP-3-1-11.html