Jetty accepts "+" prefixed value in Content-Length

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS

• CVE-2023-40167: 1.28% estimated exploitation activity in the next 30 days; percentile 70.02 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Jetty accepts the '+' character proceeding the content-length value in a HTTP/1 header field. This is more permissive than allowed by the RFC and other servers routinely reject such requests with 400 responses. There is no known exploit scenario, but it is conceivable that request smuggling could result if jetty is used in combination with a server that does not close the connection after sending such a 400 response. Workarounds There is no workaround as there is no known exploit scenario. Original Report RFC 9110 Secion 8.6 defined the value of Content-Length header should be a string of 0-9 digits. However we found that Jetty accepts "+" prefixed Content-Length, which could lead to potential HTTP request smuggling. Payload: When sending this payload to Jetty, it can successfully parse and identify the length. When sending this payload to NGINX, Apache HTTPd or other HTTP servers/parsers, they will return 400 bad request. This behavior can lead to HTTP request smuggling and…

Published by the source

14 Sep 2023, 16:17 UTC

Last modified by the source

6 Nov 2023, 05:01 UTC

Source last checked

26 Oct 2026, 16:16 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hmr7-m48g-48f6

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# Patch Next advisory brief: CVE-2023-40167

Advisory: Jetty accepts "+" prefixed value in Content-Length
IDs: CVE-2023-40167, GHSA-hmr7-m48g-48f6
Record: https://patchnext.com/advisories/cve-2023-40167 (revision 1, source checked 26 Oct 2026, 16:16 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.eclipse.jetty:jetty-http 12.0.1, 11.0.16, 10.0.16, 9.4.52. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.eclipse.jetty:jetty-http: affected >= 9.0.0, <= 9.4.51; >= 10.0.0, <= 10.0.15; >= 11.0.0, <= 11.0.15; >= 12.0.0, <= 12.0.0; fixed in 9.4.52, 10.0.16, 11.0.16, 12.0.1

## Suggested inspection (read-only)
- Maven org.eclipse.jetty:jetty-http: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.eclipse.jetty:jetty-http.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hmr7-m48g-48f6 (GitHub-reviewed advisory GHSA-hmr7-m48g-48f6 lists affected ranges: Maven org.eclipse.jetty:jetty-http >=9.0.0 =10.0.0 =11.0.0 =12.0.0 <=12.0.0)

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