---
title: "CVE-2026-2835: Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing"
url: https://erroneo.us/security/cve/CVE-2026-2835/
description: "CVE-2026-2835 (pingora-core (crates.io (Rust))): An HTTP Request Smuggling vulnerability (CWE-444) has been found in Pingora's parsing of HTTP/1.0 and…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-04
date_modified: 2026-03-09
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-2835"
kev: false
cvss: 9.3
epss: 0.00596
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-2835: Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.6% , percentile 48: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 48% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes pingora-core (crates.io (Rust)) <= 0.7.0, fixed in 0.8.0 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- crates.io (Rust) `pingora-core` <= 0.7.0 → fixed: 0.8.0

## Affected products (CVE record)

- Cloudflare https://github.com/cloudflare/pingora: < 0.8.0

## Severity

- cloudflare CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.60% probability of exploitation activity in the next 30 days; percentile 48.

## Sources

- [GitHub Advisory GHSA-hj7x-879w-vrp7](https://github.com/advisories/GHSA-hj7x-879w-vrp7)
- [CVE.org record CVE-2026-2835](https://www.cve.org/CVERecord?id=CVE-2026-2835)
- [NVD entry CVE-2026-2835](https://nvd.nist.gov/vuln/detail/CVE-2026-2835)
- [github.com](https://github.com/cloudflare/pingora)
- [github.com](https://github.com/cloudflare/pingora/security/advisories/GHSA-hj7x-879w-vrp7)
- [rustsec.org](https://rustsec.org/advisories/RUSTSEC-2026-0034.html)

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Source page: https://erroneo.us/security/cve/CVE-2026-2835/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt