Pingora forwards client-nominated Connection headers to HTTP/1 upstreams, allowing ACL bypass in specific chained deployments

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.0 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N · score source

EPSS

• CVE-2026-105299: 0.43% estimated exploitation activity in the next 30 days; percentile 36.84 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Pingora versions prior to 0.9.0 passed the downstream request through `upstream_request_filter` and wrote it to HTTP/1 upstreams 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. This 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…

Published by the source

20 Oct 2026, 12:00 UTC

Last modified by the source

26 Oct 2026, 11:15 UTC

Source last checked

26 Oct 2026, 12:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from osv record RUSTSEC-2026-0390

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# Patch Next advisory brief: CVE-2026-105299

Advisory: Pingora forwards client-nominated Connection headers to HTTP/1 upstreams, allowing ACL bypass in specific chained deployments
IDs: CVE-2026-105299, GHSA-vx4q-2c55-cvmg
Record: https://patchnext.com/advisories/cve-2026-105299 (revision 1, source checked 26 Oct 2026, 12:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pingora-proxy 0.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io pingora-proxy: affected >= 0.0.0-0, < 0.9.0; fixed in 0.9.0

## Suggested inspection (read-only)
- crates.io pingora-proxy: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pingora-proxy.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/RUSTSEC-2026-0390 (OSV record RUSTSEC-2026-0390 lists affected ranges: crates.io pingora-proxy >=0.0.0-0 <0.9.0 (fixed))

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