RUSTSEC-2026-0033: HTTP Request Smuggling via Premature Upgrade

What to do

1. See which version you have: cargo tree -i pingora-core (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p pingora-core. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example pingora-core = "0.8.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

This flaw was corrected in commit 824bdeefc61e121cc8861de1b35e8e8f39026ecd by only switching connection modes after receiving a 101 response from the backend. Users should upgrade to Pingora >= 0.8.0.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

References

• Package: crates.io/crates/pingora-core
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0033.html
• Web: blog.cloudflare.com/pingora-oss-smuggling-vulnerabilities/
• Web: nvd.nist.gov/vuln/detail/CVE-2026-2833

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for pingora-core

• VulnerabilityRUSTSEC-2025-0037 · 2025-05-22Pingora Request Smuggling and Cache Poisoning
• VulnerabilityRUSTSEC-2025-0070 · 2025-09-17Pingora MadeYouReset HTTP/2 vulnerability
• VulnerabilityRUSTSEC-2026-0034 · 2026-03-04HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
• VulnerabilityGHSA-393w-9x6h-8gc7 · 2025-09-17Pingora update for MadeYouReset HTTP/2 vulnerability

Full security history of pingora-core