Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.
This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.
Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.
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 (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).
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.
See [CVE-2026-2835](https://www.cve.org/CVERecord?id=CVE-2026-2835) and the [Cloudflare blog post](https://blog.cloudflare.com/pingora-oss-smuggling-vulnerabilities/) for more details.
Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare [Bug Bounty Program](https://www.cloudflare.com/disclosure/).
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVE-2026-2835 is classified as CWE-444: HTTP Request Smuggling. A proxy and a server disagree on where one request ends, letting an attacker slip a second request past the front end.
CVE-2026-2835 is recorded against 2 packages.
Published on 5 March 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.
pingora has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-444: HTTP Request Smuggling) in other software:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| pingora | — | 0.8.0 |
| pingora-core | — | — |
References
Similar Threats
Exploit Protection
CVE-2026-2835 carries CVSS 9.5 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.
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