CVE-2026-2835
HTTP Request Smuggling in Pingora Enables Proxy Bypass and Cache Poisoning
Publication date: 2026-03-05
Last updated on: 2026-03-12
Assigner: Cloudflare, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| cloudflare | pingora | to 0.8.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-444 | The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is an HTTP Request Smuggling issue found in Pingora's handling of HTTP/1.0 and Transfer-Encoding requests. It happens because Pingora improperly allows HTTP/1.0 request bodies to be close-delimited and incorrectly handles multiple Transfer-Encoding values. This flaw lets attackers send specially crafted HTTP/1.0 requests that cause Pingora's request framing to become desynchronized from backend servers.
How can this vulnerability impact me? :
This vulnerability mainly affects standalone Pingora deployments in front of backends that accept HTTP/1.0 requests. An attacker could exploit it to:
- Bypass proxy-level access control lists (ACL) and Web Application Firewall (WAF) logic.
- Poison caches and upstream connections, causing legitimate users to receive responses meant for smuggled requests.
- Perform cross-user attacks by hijacking sessions or smuggling requests that appear to come from the trusted proxy IP.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, users should upgrade to Pingora version 0.8.0 or higher, which fixes the 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 to stop processing bytes on the connection and disable downstream connection reuse.
- Reject any non-HTTP/1.1 request.
- Reject requests with invalid Content-Length headers.
- Reject requests with multiple Transfer-Encoding headers.
- Reject requests where the Transfer-Encoding header is not an exact “chunked” string match.