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🛡️ CVE-2026-2833 — pingora

🔴 CVSS 9.5 — Critical ✅ No Known Exploit CWE-444 NVD
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Pingora vulnerable to HTTP Request Smuggling via Premature Upgrade

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

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, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were 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.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

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.

References

See [CVE-2026-2833](https://www.cve.org/cverecord?id=CVE-2026-2833) and the [Cloudflare blog post](https://blog.cloudflare.com/pingora-oss-smuggling-vulnerabilities/) for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare [Bug Bounty Program](https://www.cloudflare.com/disclosure/).

How this vulnerability can be exploited

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.

CVSS metrics in full

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

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-2833 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.

Affected software

CVE-2026-2833 is recorded against 2 packages.

  • pingora (fixed in 0.8.0)
  • pingora-core

Timeline and source

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.

References

github.com

Other advisories for this package

pingora has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-444: HTTP Request Smuggling) in other software:

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE CWE-444
Public Exploit ✅ No
Source NVD
Published 2026-03-05
Updated 2026-08-20
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
pingora — 0.8.0
pingora-core — —

Similar Threats

Exploit Protection

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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