CVE-2023-34062: 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 u

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HIGH 7.5REMOTEUPGRADE

CVE-2023-34062 is a high-severity flaw (CVSS 7.5) affecting reactor netty. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 34%)
CISA exploited list	No
Weakness	CWE-22
Published	2023-11-15
Last modified	2026-09-04

Publisher (CNA): VMware · Vendor: broadcom

Last updated 2026-09-04 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-11-15 10:15 UTCPublished CVE record published
2026-09-04 18:59 UTCUpdated Record last modified

broadcom reactor netty UPGRADE

Affected: >= 1.0.0 and < 1.0.39 · >= 1.1.0 and < 1.1.13

Fixed in: 1.0.39, 1.1.13

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy reactor-netty || rpm -q reactor-netty || reactor-netty --version

2. UPGRADE to 1.0.39 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade reactor-netty

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade reactor-netty

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison reactor-netty sudo apt install reactor-netty=<VERSION_BEFORE_1.0.0> sudo apt-mark hold reactor-netty

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list reactor-netty sudo dnf downgrade reactor-netty-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add reactor-netty

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-34062?

reactor netty: upgrade to 1.0.39, 1.1.13. Exact commands for each OS are on this page.

Is CVE-2023-34062 being exploited?

CVE-2023-34062 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-34062 affect?

CVE-2023-34062 affects reactor netty. Severity is high (CVSS 7.5). 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

How urgent is CVE-2023-34062?

Priority 48/100. High severity; Remotely exploitable, no login, no user action

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CVE-2020-5403 HIGH 7.5 DOWNGRADE Reactor Netty HttpServer, versions 0.9.3 and 0.9.4, is exposed to a URISyntaxException that causes the connect

References

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