CVE-2025-67485: 
Python vulnerability analysis and mitigation

CVE-2025-67485 is an HTTP/HTTPS traffic interception bypass vulnerability in mad-proxy, a Python-based proxy server built on mitmproxy for detecting and blocking malicious web activity. It affects mad-proxy versions 0.3 and below, allowing network-accessible attackers to evade the proxy's filtering and interception rules without any privileges or user interaction. The vulnerability was published on December 7, 2025, by the maintainer (machphy) and added to the GitHub Advisory Database on December 9, 2025. It carries a CVSS v3.1 base score of 5.3 (Medium) (Github Advisory, GitHub Security Advisory).

The vulnerability is classified under CWE-693 (Protection Mechanism Failure), meaning the proxy's traffic interception and policy enforcement mechanism can be bypassed due to incorrect or incomplete implementation. mad-proxy is designed to transparently intercept HTTP/HTTPS traffic and enforce domain-level block/allow rules defined in a YAML configuration file; however, attackers can craft requests or leverage protocol-level techniques to circumvent these interception rules. No privileges are required, and the attack can be performed remotely over the network with low complexity. No detailed public technical write-up or proof-of-concept code has been published beyond the advisory itself (Github Advisory, GitHub Security Advisory).

Successful exploitation allows attackers to bypass the proxy's HTTP/HTTPS traffic interception rules, causing sensitive web traffic to pass through uninspected and unblocked. The primary impact is a confidentiality loss — traffic that should be intercepted, logged, or blocked by security policy may instead reach its destination undetected. Integrity and availability are not directly affected. Organizations relying on mad-proxy for adversary simulation, defensive validation, or real-time policy enforcement may find their security controls silently ineffective (Github Advisory).

There is no known public exploit code, active in-the-wild exploitation, or threat actor attribution associated with CVE-2025-67485 at this time. The EPSS score is approximately 0.056% (18th percentile), indicating a low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Given the niche deployment context of mad-proxy (primarily used by security researchers and red teamers), the practical attack surface is limited (Github Advisory).

The maintainer has released mad-proxy version 0.4, which addresses this vulnerability; users should upgrade immediately (GitHub Security Advisory). The project's README explicitly advises upgrading to v0.4+ to remain protected (mad-proxy repo). No configuration-based workarounds have been documented; upgrading to the patched version is the only recommended remediation.

The advisory was noted by automated vulnerability tracking services including CIRCL Vulnerability Lookup, CVEFeed, and Vulners shortly after publication. A brief mention appeared on Bluesky via a CVE tracking account. No significant commentary from prominent security researchers or broader media coverage has been identified for this vulnerability, consistent with its niche scope and moderate severity.