CVE-2026-105299 — Pingora forwards client-nominated Connection headers to HTTP/1 upstreams, allowing ACL bypass in specific chained deployments
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.3% (30-day exploitation probability)+4
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Cloudflare Https://github.com/cloudflare/pingora).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Cloudflare | Https://github.com/cloudflare/pingora | ≥ 0.1.0 and < 0.9.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 8.7 | CVSS 3.1 | High | 2.2 | 5.8 | cna@cloudflare.com via NIST National Vulnerability Database |
| 8.7 | CVSS 3.1 | High | — | — | cloudflare via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N (score shown at the top: cna@cloudflare.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 20, 2026 → Oct 21, 2026 · 2 reading(s) · max 0.34%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Look for parameters with command/query metacharacters and unexpected child processes of the service.
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Source status changed · Received → Awaiting Analysis
- Affected products added · cloudflare/https://github.com/cloudflare/pingora
- Record published
- CVSS changed · 8.7
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 19, 2026 – Oct 19, 2026
- 1× Official description updated · Oct 19, 2026 – Oct 19, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-105297 Pingora HTTP/2 server memory exhaustion through unbounded default header-list and concurrent-stream limits 2d
- Medium CVE-2026-105298 Pingora HTTP/2 :authority and Host header mismatch enables cache poisoning and host-based access control bypass 2d
- High CVE-2026-2836 Cache poisoning via insecure-by-default cache key Mar 4, 2026
- Critical CVE-2026-2833 HTTP Request Smuggling via Premature Upgrade Mar 4, 2026
- Critical CVE-2026-2835 HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing Mar 4, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-105299 is "Pingora forwards client-nominated Connection headers to HTTP/1 upstreams, allowing ACL bypass in specific chained deployments", rated High. It affects Https://github.com/cloudflare/pingora (Cloudflare); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.7 describes technical severity. EPSS 0.34% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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