---
id: "CVE-2026-105299"
kind: "vulnerability"
aliases: ["CVE-2026-105299"]
title: "Pingora proxy: client Connection header can strip origin-trusted headers"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "pingora", "reverse-proxy", "rust", "self-hosted"]
not_affected_if: ["cloudflare-cdn-only", "no-chained-http1-intermediary", "origin-ignores-proxy-headers"]
published_at: "2026-10-20T02:17:08+00:00"
first_seen_at: "2026-10-23T21:57:19+00:00"
updated_at: "2026-10-23T22:37:24+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105299", "first_seen_at": "2026-10-23T21:57:19+00:00"}]
---

# Pingora proxy: client Connection header can strip origin-trusted headers

Before pingora 0.9.0, the HTTP/1 upstream path forwarded the client's Connection header and the headers it names, so a client can make a downstream HTTP/1 intermediary delete headers Pingora added, such as X-Forwarded-For. An unauthenticated remote attacker can thereby bypass IP-based authorization at the origin.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

Check whether the pingora crate in Cargo.lock is below 0.9.0.
Check whether an HTTP/1 intermediary (e.g. Go httputil.ReverseProxy) sits between Pingora and the origin.
Check whether the origin authorizes requests based on headers added by Pingora.

## Fix

Upgrade pingora to 0.9.0 or later, keeping the default HttpUpstreamRequestPolicy (do not use preserve()).
If upgrading is not possible, remove Connection and every header it nominates in upstream_request_filter before adding trusted headers.

## Timeline

- 2026-10-23T21:57:19+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-105299

## From the sources

Summary



Before version 0.9.0, the HTTP/1 upstream path in pingora-proxy passed the downstream request through upstream_request_filter and wrote it to the upstream without removing the client's Connection header, other hop-by-hop headers, or the headers Connection nominated, although RFC 9110 Section 7.6.1 requires intermediaries to remove them. The HTTP/2 upstream path already removed Connection and related HTTP/1-specific headers. A client could therefore nominate a header that the application adds in upstream_request_filter (for example, Connection: keep-alive, X-Forwarded-For). A downstream HTTP/1 intermediary that honors Connection would then strip the Pingora-added header before it reached the origin.




Impact



Specifically affects chained deployments where an HTTP/1 intermediary between Pingora and the origin processes Connection nominations (for example, Go's net/http/httputil.ReverseProxy) and the origin trusts headers added by that intermediary (for example, X-Forwarded-For for IP-based authorization). A remote, unauthenticated attacker can have those headers removed, potentially bypassing authorization. The reporter demonstrated access to an IP-restricted endpoint using X-Forwarded-For for IP validation on the origin. This is the same class of issue as CVE-2022-31813 in Apache HTTP Server.




Note that Cloudflare CDN customers were unaffected, as no such chained deployment as described above exists with internal Pingora services, and Connection headers are sanitized before arriving at Pingora gateways.



Mitigation:

  *  

Upgrade to pingora 0.9.0 or later. By default, Pingora now removes hop-by-hop and Connection-nominated headers from upstream requests, and rejects requests whose Connection header nominates Host, X-Forwarded-For, X-Forwarded-Host, X-Forwarded-Proto, or a pseudo-header. This is controlled by PeerOptions::http_upstream_request_policy (HttpUpstreamRequestPolicy). Fix commits:  https://github.com/cloudflare/pingora/commit/28c18e6b6b04dd0bd937234e5950049e6d74cded ,  https://github.com/cloudflare/pingora/commit/ca23f1668eca8e78be7ba62ef0edbd458b40eeee 


  *  

Do not use HttpUpstreamRequestPolicy::preserve() if the origin relies on headers added by Pingora; it restores the old passthrough behavior.


  *  

If you cannot upgrade: in upstream_request_filter, remove the Connection header and every header it nominates before adding trusted headers.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_