Cloudflare has fixed several Pingora vulnerabilities that could allow attackers to smuggle HTTP requests through poison caches and edge proxies, creating avenues for data exposure, cross-tenant leaks, and the large-scale delivery of malicious content This article explores vulnerability pingora proxy. . Pingora's shortcomings include poisoned caches and parsing errors.

Cloudflare's Rust-based proxy framework, Pingora, is utilized both internally and by external adopters. Pingora-cache and related crates offer optional caching. A high-severity HTTP/1.1 request smuggling vulnerability in Pingora's proxy layer that directly allowed cache poisoning on cache hits was revealed by Cloudflare in May 2025 as CVE-2025-4366. Because Pingora served a cached response without completely draining the incoming HTTP/1.1 request body before reusing the connection, attacker-controlled bytes in the buffer could be mistakenly interpreted as a separate request.

Both will be mistakenly interpreted by Pingora as the same upgraded request. Security researchers demonstrated that a single crafted request could inject a "smuggled" follow-up request, giving an attacker the ability to change the headers and URLs that the origin sees and affect what is cached. CI security checks should include routine testing for request smuggling and cache poisoning, particularly where HTTP/1.1 keep-alive and shared caches converge.