CVE-2023-34062 In Reactor Netty HTTP Server a malicious user can send a request using a specially crafted URL that can lead to a directory traversal attack

What is CVE-2023-34062?

CVE-2023-34062 is a high-severity path traversal vulnerability in Reactor Netty, published on 15 Nov 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In Reactor Netty HTTP Server, versions 1.1.x prior to 1.1.13 and versions 1.0.x prior to 1.0.39, a malicious user can send a request using a specially crafted URL that can lead to a directory traversal attack.

Specifically, an application is vulnerable if Reactor Netty HTTP Server is configured to serve static resources.

Weakness: CWE-22

Which versions are affected by CVE-2023-34062?

4 open source packages ship an affected version, including io.projectreactor.netty:reactor-netty-http. It affects 1 product.

Products include Broadcom Reactor Netty.

How do I fix CVE-2023-34062?

Upgrade io.projectreactor.netty:reactor-netty-http to a fixed version for your release line: 1.0.39 or 1.1.13.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2023-34062 being exploited?

There is no known exploitation of CVE-2023-34062 in the wild and no public exploit code.

Other vulnerabilities in Reactor Netty

• CVE-2019-11284 Reactor Netty authentication leak in redirects Medium 6.8
• CVE-2020-5403 DoS Via Malformed URL with Reactor Netty HTTP Server Medium 6.5
• CVE-2020-5404 Authentication Leak On Redirect With Reactor Netty HttpClient Medium 6.5
• CVE-2026-47848 Reactor Netty WebSocket Client Leaks Credentials On Redirect Medium 6.1
• CVE-2026-47844 Reactor Netty HTTP Server Leaks Exception Details Medium 5.3

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLSA-2026-1776126825, GHSA-xjhv-p3fv-x24r, ROOT-APP-MAVEN-CVE-2023-34062.