HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
Description
An HTTP Request Smuggling vulnerability (CWE-444) has been found in Pingora's parsing of HTTP/1.0 and Transfer-Encoding requests. The issue occurs due to improperly allowing HTTP/1.0 request bodies to be close-delimited and incorrect handling of multiple Transfer-Encoding values, allowing attackers to send HTTP/1.0 requests in a way that would desync Pingora’s request framing from backend servers’.
Impact
This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could craft a malicious payload following this request that Pingora forwards to the backend in order to:
- Bypass proxy-level ACL controls and WAF logic
- Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests
- Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP
Cloudflare's CDN infrastructure was not affected by this vulnerability, as its ingress proxy layers forwarded HTTP/1.1 requests only, rejected ambiguous framing such as invalid Content-Length values, and forwarded a single Transfer-Encoding: chunked header for chunked requests.
Mitigation:
Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited.
As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Pingora HTTP/1.0 and Transfer-Encoding parsing flaw enables request smuggling, potentially bypassing security controls and poisoning caches.
Vulnerability
Description
An HTTP Request Smuggling vulnerability (CWE-444) exists in Pingora's parsing of HTTP/1.0 and Transfer-Encoding requests. The root cause is that Pingora improperly allows HTTP/1.0 request bodies to be close-delimited and incorrectly handles multiple Transfer-Encoding values. This discrepancy between how Pingora and backend servers interpret message boundaries allows attackers to craft requests that desync Pingora's request framing from that of the backend [1][2][4].
Exploitation
An attacker can send a specially crafted HTTP/1.0 request with ambiguous Content-Length or Transfer-Encoding headers to trigger the smuggling. The attack requires the Pingora proxy to be deployed in front of backend servers that accept HTTP/1.0 requests. By smuggling a malicious request after the initial one, the attacker can cause the backend to interpret a subsequent request as part of the smuggled payload [4]. Cloudflare's CDN infrastructure was not affected because its ingress layers reject ambiguous framing and ensure only HTTP/1.1 requests with unambiguous Transfer-Encoding are forwarded [1].
Impact
Successful exploitation can lead to bypassing proxy-level access control lists (ACLs) and Web Application Firewall (WAF) logic. Additionally, the attacker can poison caches and upstream connections, causing subsequent legitimate users to receive responses intended for smuggled requests. Cross-user attacks are also possible by hijacking sessions or making smuggled requests appear to originate from the trusted proxy IP [1][4].
Mitigation
Pingora users should upgrade to version 0.8.0 or higher, which fixes the issue by strictly adhering to RFC 9112 for message length parsing and disallowing close-delimited HTTP/1.0 request bodies. As a workaround, users can implement request filter logic to reject any non-HTTP/1.1 requests or requests with invalid Content-Length, multiple Transfer-Encoding headers, or a Transfer-Encoding header that is not an exact "chunked" match [4].
AI Insight generated on May 18, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
pingora-corecrates.io | < 0.8.0 | 0.8.0 |
Affected products
2- Range: <0.8.0
- Cloudflare/https://github.com/cloudflare/pingorav5Range: 0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4News mentions
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