CVE-2026-105299
8.7HighPublished 20 Oct 2026 · NVD status: Received · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
- Impact
- High impact on confidentiality, integrity
- Weakness
- —
Impact
Remote unauthenticated attackers can strip trusted headers like X-Forwarded-For to bypass origin access controls. This requires a chained HTTP/1 intermediary between Pingora and the origin that processes Connection header nominations.
Root cause
The HTTP/1 upstream path forwarded client Connection headers and nominated hop-by-hop headers to upstream proxies instead of stripping them per RFC 9110.
Affected systems
pingora-proxy before 0.9.0
CVSS v3.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Fix & remediation
Upgrade pingora to 0.9.0 or later and avoid using HttpUpstreamRequestPolicy::preserve(). If you cannot upgrade immediately, manually strip the incoming Connection header and any headers it nominates inside upstream_request_filter before inserting trusted headers.
$ cargo update -p pingora-proxy --precise 0.9.0AI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
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.