How severe is CVE-2023-40167?

CVE-2023-40167 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-40167?

CVE-2023-40167 affects the following packages: org.eclipse.jetty:jetty-http (Maven), org.eclipse.jetty:jetty-http (Maven), org.eclipse.jetty:jetty-http (Maven), org.eclipse.jetty:jetty-http (Maven). Ecosystems affected: Maven.

How do I fix CVE-2023-40167?

Update org.eclipse.jetty:jetty-http to 9.4.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40167 is resolved across your whole dependency graph.

How do I detect CVE-2023-40167 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.eclipse.jetty:jetty-http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-40167 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2023-40167 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-40167 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-40167?

CVE-2023-40167 has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 70th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-40167?

CVE-2023-40167 is classified as CWE-130 (CWE-130). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-40167 published, and has it been updated?

CVE-2023-40167 was published on September 15, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2023-40167 — jetty-http

MEDIUM

CVE-2023-40167 is a medium-severity (CVSS 5.3) CWE-130 vulnerability in org.eclipse.jetty:jetty-http. A fix is available for org.eclipse.jetty:jetty-http — see the affected versions and patch details below.

Jetty accepts "+" prefixed value in Content-Length

Also known asGHSA-hmr7-m48g-48f6

Published

Sep 15, 2023

Updated

Oct 28, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-40167.

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs70th percentile — riskier than 70% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected

☕org.eclipse.jetty:jetty-http☕org.eclipse.jetty:jetty-http☕org.eclipse.jetty:jetty-http☕org.eclipse.jetty:jetty-http

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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:

 POST / HTTP/1.1
 Host: a.com
 Content-Length: +16
 Connection: close
 
 0123456789abcdef

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 can be leveraged to bypass WAF or IDS.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.eclipse.jetty:jetty-http`	≥ 9.0.0&&< 9.4.52	9.4.52`org.eclipse.jetty:jetty-http:9.4.52`
☕Maven	`org.eclipse.jetty:jetty-http`	≥ 10.0.0&&< 10.0.16	10.0.16`org.eclipse.jetty:jetty-http:10.0.16`
☕Maven	`org.eclipse.jetty:jetty-http`	≥ 11.0.0&&< 11.0.16	11.0.16`org.eclipse.jetty:jetty-http:11.0.16`
☕Maven	`org.eclipse.jetty:jetty-http`	≥ 12.0.0&&< 12.0.1	12.0.1`org.eclipse.jetty:jetty-http:12.0.1`

Affected Products

2 products · 12 configurations

debian linuxdebian

3 versions

10.011.012.0

Application

jettyeclipse

≥ 11.0.0 && < 11.0.16

1 version

12.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.eclipse.jetty:jetty-http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.eclipse.jetty:jetty-http to 9.4.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40167 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
OCP-Tools-4.12-RHEL-8	`jenkins-0:2.426.3.1706515686-3.el8`	RHSA-2024:0778
Red Hat AMQ Broker 7	`jetty-http`	RHSA-2023:5946
Red Hat AMQ Clients	`jetty-http`	RHSA-2023:7697
Red Hat AMQ Streams 2.6.0	`jetty-http`	RHSA-2023:7678
Red Hat Fuse 7.12.1	`jetty`	RHSA-2023:7247
Red Hat Fuse 7.13.0	`jetty`	RHSA-2024:3354
Red Hat Integration Camel Quarkus 2	`jetty-http`	RHSA-2023:5780
Red Hat Satellite 6.14 for RHEL 8	`candlepin-0:4.3.11-1.el8sat`	RHSA-2024:0797

Frequently Asked Questions

### 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](https://www.rfc-editor.org/rfc/rfc911