CVE-2022-36032 is a vulnerability found in the ReactPHP HTTP server component, specifically affecting versions from 0.7.0 up to but not including 1.7.0. ReactPHP HTTP is a streaming HTTP client and server implementation widely used in PHP asynchronous applications. The vulnerability arises from improper input validation during the processing of incoming HTTP cookie values. ReactPHP's HTTP server decodes cookie names using URL decoding, which can cause cookies with certain prefixes, such as '__Host-' and '__Secure-', to be confused with other cookies that decode to these prefixes. These prefixes are critical because they are used to enforce security properties on cookies, such as restricting them to secure contexts or specific hosts. By exploiting this flaw, an attacker can forge cookies that appear to have these secure prefixes, potentially bypassing security controls that rely on these prefixes to protect cookie integrity and confidentiality. This could lead to session fixation, privilege escalation, or other cookie-based attacks. The issue was addressed in ReactPHP HTTP version 1.7.0 by correcting the input validation and cookie name handling. Until systems are updated, a recommended workaround is to deploy a reverse proxy in front of the ReactPHP HTTP server to filter out unexpected or malformed 'Cookie' headers, thereby mitigating the risk of exploitation. No known exploits have been reported in the wild, but the vulnerability poses a moderate risk due to its potential to undermine cookie security mechanisms.

For European organizations, this vulnerability could have significant implications, especially for those relying on ReactPHP HTTP server components in their web applications or services. The ability to forge cookies with secure prefixes may enable attackers to bypass cookie-based security policies, leading to unauthorized access, session hijacking, or data leakage. This is particularly concerning for sectors handling sensitive personal data under GDPR, such as finance, healthcare, and e-commerce. The compromise of cookie integrity can undermine user authentication and session management, potentially leading to broader system compromise. Additionally, organizations that provide critical infrastructure or public-facing services using ReactPHP HTTP may face reputational damage and regulatory penalties if exploited. Although no active exploits are currently known, the medium severity rating and the nature of the vulnerability warrant prompt attention to prevent potential attacks.

1. Immediate upgrade of ReactPHP HTTP server components to version 1.7.0 or later, where the vulnerability is fixed, should be prioritized. 2. Until upgrades can be applied, deploy a reverse proxy (e.g., Nginx, Apache, or dedicated WAF) in front of the ReactPHP HTTP server to filter and validate incoming 'Cookie' headers, specifically blocking or sanitizing cookies with suspicious or malformed names that could exploit the decoding flaw. 3. Implement strict cookie security policies on the application side, including HttpOnly, Secure, and SameSite attributes, to reduce the impact of forged cookies. 4. Conduct thorough security testing and code reviews focusing on cookie handling and input validation in applications using ReactPHP HTTP. 5. Monitor logs for unusual cookie-related activity or anomalies in HTTP headers that could indicate exploitation attempts. 6. Educate DevOps and infrastructure teams about this vulnerability and ensure patch management processes include ReactPHP components. 7. Consider implementing additional layers of session validation, such as token binding or multi-factor authentication, to mitigate risks from cookie forgery.