CVE-2024-45614: Puma is a Ruby/Rack web server built for parallelism

Routine

MEDIUM 5.4REMOTEUPGRADE

CVE-2024-45614 is a medium-severity flaw (CVSS 5.4) affecting puma. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users relying on proxy set variables is affected. v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. Use

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 49%)
CISA exploited list	No
Weakness	CWE-639, CWE-444
Published	2024-09-19
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: puma

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2024-09-19 23:15 UTCPublished CVE record published
2026-06-17 07:54 UTCUpdated Record last modified

puma puma UPGRADE

Affected: < 5.6.9 · >= 6.0.0 and < 6.4.3

Fixed in: 5.6.9, 6.4.3

Safe to downgrade to: a release before 6.0.0

1. Check installed version

apt-cache policy puma || rpm -q puma || puma --version

2. UPGRADE to 5.6.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade puma

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade puma

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 6.0.0 (Debian / Ubuntu)

apt-cache madison puma sudo apt install puma=<VERSION_BEFORE_6.0.0> sudo apt-mark hold puma

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

dnf --showduplicates list puma sudo dnf downgrade puma-<VERSION_BEFORE_6.0.0> sudo dnf versionlock add puma

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-2024-45614?

puma: upgrade to 5.6.9, 6.4.3. Exact commands for each OS are on this page.

Is CVE-2024-45614 being exploited?

CVE-2024-45614 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-2024-45614 affect?

CVE-2024-45614 affects puma. Severity is medium (CVSS 5.4). Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users

How urgent is CVE-2024-45614?

Priority 37/100. Remotely exploitable, no login, no user action

Software pages

Ruby vulnerabilities

Related CVEs

CVE-2024-21647 MEDIUM 5.9 UPGRADE Puma is a web server for Ruby/Rack applications built for parallelism
CVE-2023-40175 HIGH 7.3 UPGRADE Puma is a Ruby/Rack web server built for parallelism

References

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