Description
In PHP versions 7.2.x below 7.2.34, 7.3.x below 7.3.23 and 7.4.x below 7.4.11, when PHP is processing incoming HTTP cookie values, the cookie names are url-decoded. This may lead to cookies with prefixes like __Host confused with cookies that decode to such prefix, thus leading to an attacker being able to forge cookie which is supposed to be secure. See also CVE-2020-8184 for more information.
Remediation
References
Related Vulnerabilities
phpBB Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2008-7143)
PHP Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2010-2100)
WebLogic Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2017-10334)
WordPress Plugin User Login Log Cross-Site Scripting (2.2.2)
Squid Insufficient Verification of Data Authenticity Vulnerability (CVE-2016-4553)