USN-4442-1: Sympa vulnerabilities

Michael Kaczmarczik discovered that Sympa incorrectly handled HTTP
GET/POST requests. An attacker could possibly use this issue to insert,
edit or obtain sensitive information. (CVE-2018-1000550)

It was discovered that Sympa incorrectly handled URL parameters. An
attacker could possibly use this issue to perform XSS attacks.
(CVE-2018-1000671)

Nicolas Chatelain discovered that Sympa incorrectly handled environment
variables. An attacker could possibly use this issue with a setuid
binary and gain root privileges. (CVE-2020-10936)