GHSA-862m-5253-832r: 
PHP vulnerability analysis and mitigation

The Auth0 WordPress plugin contains a critical vulnerability (GHSA-862m-5253-832r, CVE-2025-48951) related to insecure deserialization of cookie data, discovered and disclosed in June 2025. The vulnerability affects versions 5.0.0-BETA0 through 5.0.1 of the WordPress plugin that uses Auth0-PHP SDK versions 8.0.0-BETA3 to 8.3.0 (GitHub Advisory, Wiz Report).

The vulnerability stems from the insecure deserialization of cookie data in the Auth0 WordPress plugin, classified as CWE-502 (Deserialization of Untrusted Data). The issue is particularly critical because the SDKs process cookie content without prior authentication, allowing potential exploitation through specially crafted cookies containing malicious serialized data. The vulnerability has received a CVSS v4.0 base score of 9.3, with the vector string CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H (Auth0 Advisory).

The vulnerability's exploitation could lead to significant security breaches with high impact on system integrity and subsequent system confidentiality, integrity, and availability. While the vulnerable system's confidentiality might not be directly impacted, there are high risks to integrity, and the subsequent systems face high risks across all security aspects (NVD CVE).

The recommended mitigation is to upgrade the Auth0 WordPress plugin to version 5.3.0 or later, which contains the security patch. This update addresses the deserialization vulnerability and implements proper cookie data validation (GitHub Advisory).