WordPress before 5.2.4 is vulnerable to poisoning of the cache of JSON GET requests because certain requests lack a Vary: Origin header.
https://www.debian.org/security/2020/dsa-4677
https://www.debian.org/security/2020/dsa-4599
https://wpvulndb.com/vulnerabilities/9911
https://wordpress.org/news/2019/10/wordpress-5-2-4-security-release/
https://seclists.org/bugtraq/2020/Jan/8
https://github.com/WordPress/WordPress/commit/b224c251adfa16a5f84074a3c0886270c9df38de