Chunk extension request smuggling

The Eclipse Foundation is a Common Vulnerabilities and Exposures (CVE) Numbering Authority. This issue it used to request and track the progress of the assignment of a CVE for a vulnerability in the project code for an Eclipse open source project.

Basic information

Project name: Eclipse Jetty

Project id: rt/jetty

Request type: reservation

Versions affected:

  >=12.1.0,<=12.1.6
  >=12.0.0,<=12.0.32
  >=11.0.0, <=11.0.27
  >=10.0.0, <=10.0.27
  >=9.4.0, <=9.4.59

Common Weakness Enumeration (CWE):

• CWE-444

Common Attack Pattern Enumerations and Classifications (CAPEC):

• None

Common Vulnerability Scoring System: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Summary:

In Eclipse Jetty, the HTTP/1.1 parser is vulnerable to request smuggling when chunk extensions are used, similar to the "funky chunks" techniques outlined here:

• https://w4ke.info/2025/06/18/funky-chunks.html
• https://w4ke.info/2025/10/29/funky-chunks-2.html

Jetty terminates chunk extension parsing at \r\n inside quoted strings instead of treating this as an error.

POST / HTTP/1.1
Host: localhost
Transfer-Encoding: chunked

1;ext="val
X
0

GET /smuggled HTTP/1.1
...

Note how the chunk extension does not close the double quotes, and it is able to inject a smuggled request.

Links:

• https://github.com/jetty/jetty.project/security/advisories/GHSA-355h-qmc2-wpwf

Credits: ...

• https://github.com/xclow3n

Tracking

This section will completed by the project team.

• Reserve an entry only
• We're ready for this issue to be reported to the central authority (i.e., make this public now)
• (when applicable) The GitHub Security Advisory is ready to be published now

Note that for those projects that host their repositories on GitHub, the use of GitHub Security Advisories is recommended but is not required.

This section will be completed by the EMO.

CVE: {cve}

• All required information is provided
• CVE Assigned
• Pushed to Mitre
• Accepted by Mitre