CVE-2026-2836: Pingora vulnerable to cache poisoning via insecure-by-default cache key

Pingora versions prior to 0.8.0 generated cache keys using only the URI path, excluding critical factors such as the host header. This allows an attacker to poison the cache and serve cross-origin responses to users.

This vulnerability affects users of Pingora’s alpha proxy caching feature who relied on the default CacheKey implementation. An attacker could exploit this for cross-tenant data leakage in multi-tenant deployments, or serve malicious content to legitimate users by poisoning shared cache entries.

Note: Cloudflare customers and Cloudflare’s CDN infrastructure were not affected by this vulnerability, as Cloudflare’s default cache key implementation uses multiple factors to prevent cache key poisoning and never made use of the previously provided default.