CVE-2026-2833

An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking. Impact This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this 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 ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode. Mitigation: Pingora users should upgrade to Pingora v0.8.0 or higher As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

• CWE-444

• https://github.com/cloudflare/pingoraProduct

Published

Mar 5, 2026

Last Modified

Jun 17, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-28317SolarWinds Serv-U is affected by an insecure direct object r…9.1
• CVE-2026-28318SolarWinds Serv-U is susceptible to specially crafted POST r…7.5
• CVE-2026-2832Certain Samsung MultiXpress Multifunction Printers may be vu…5.3
• CVE-2026-28321SolarWinds Serv-U is affected by a broken access control vul…9.1
• CVE-2026-28322SolarWinds Database Performance Analyzer was found to be aff…5.6
• CVE-2026-28323SolarWinds Web Help Desk is found to be affected by a SAML a…9.8
• CVE-2026-28338PMD is an extensible multilanguage static code analyzer. Pri…6.1
• CVE-2026-2834The Age Verification & Identity Verification by Token of Tru…7.2
• CVE-2026-28342OliveTin gives access to predefined shell commands from a we…7.5
• CVE-2026-28343CKEditor 5 is a modern JavaScript rich-text editor with an M…6.1
• CVE-2026-28348lxml_html_clean is a project for HTML cleaning functionaliti…6.1
• CVE-2026-2835An HTTP Request Smuggling vulnerability (CWE-444) has been f…9.1