CVE-2026-2835
published 2026-03-05CVE-2026-2835: 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…
PriorityP359critical9.1CVSS 3.1
AVNACLPRNUINSUCHIHAN
EPSS
0.71%
48.8th percentile
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
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| cloudflare | https_github.com_cloudflare_pingora | < 0.8.0 | 0.8.0 |
| cloudflare | pingora | < 0.8.0 | 0.8.0 |
CVSS provenance
nvdv3.19.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
nvdv4.09.3CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
ghsa9.3CRITICAL
osv9.3CRITICAL
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OSV
Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
osv·2026-03-05·CVSS 9.3
CVE-2026-2835 [CRITICAL] Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
### Impact
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 laye
GHSA
Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
ghsa·2026-03-05·CVSS 9.3
CVE-2026-2835 [CRITICAL] CWE-444 Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
Pingora has HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
### Impact
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 laye
OSV
HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
osv·2026-03-04
CVE-2026-2835 HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
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.
This flaw was corrected in commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d047262
No detection rules found.
No public exploits indexed.
2026-03-05
Published