Request smuggling via empty transfer-coding element
Published Mar 20, 2025 · Updated Oct 15, 2025
HTTP request smuggling in Benoît Chesneau Gunicorn before 22.0.0 allows remote attackers to desynchronize proxied HTTP requests. The HTTP parser treats a Transfer-Encoding value such as ",chunked" as unsupported and falls back to Content-Length instead of recognizing chunked framing. Exploitation requires a gateway that interprets the malformed header as chunked and reuses the backend connection, enabling cross-request data exposure or cache poisoning.
Summary
What happened
HTTP request smuggling in Benoît Chesneau Gunicorn before 22.0.0 allows remote attackers to desynchronize proxied HTTP requests. The HTTP parser treats a Transfer-Encoding value such as ",chunked" as unsupported and falls back to Content-Length instead of recognizing chunked framing. Exploitation requires a gateway that interprets the malformed header as chunked and reuses the backend connection, enabling cross-request data exposure or cache poisoning.
The record
- CVE
- CVE-2024-6827
- Published
- Mar 20, 2025
- Updated
- Oct 15, 2025
- Vendor
- Benoît Chesneau
- Product
- Gunicorn
- Classifications
- CWE-444, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 20, 2025CVE publishedPublication date reported by the CVE source.
- Oct 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <=latest
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Improper handling of empty Transfer-Encoding list elementsproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo