How severe is GHSA-c2f4-cvqm-65w2?

GHSA-c2f4-cvqm-65w2 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-c2f4-cvqm-65w2?

GHSA-c2f4-cvqm-65w2 affects the following packages: puma (RubyGems), puma (RubyGems). Ecosystems affected: RubyGems.

How do I fix GHSA-c2f4-cvqm-65w2?

Update puma to 6.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c2f4-cvqm-65w2 is resolved across your whole dependency graph.

How do I detect GHSA-c2f4-cvqm-65w2 in my RubyGems dependencies?

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

How do I mitigate GHSA-c2f4-cvqm-65w2 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 GHSA-c2f4-cvqm-65w2 actively exploited in the wild?

No public exploit code has been indexed for GHSA-c2f4-cvqm-65w2 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 GHSA-c2f4-cvqm-65w2?

GHSA-c2f4-cvqm-65w2 has an EPSS (Exploit Prediction Scoring System) score of 1.0%, placing it in the 62th 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 GHSA-c2f4-cvqm-65w2?

GHSA-c2f4-cvqm-65w2 is classified as CWE-444 (CWE-444). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-c2f4-cvqm-65w2 published, and has it been updated?

GHSA-c2f4-cvqm-65w2 was published on January 8, 2024 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎

💎 RubyGems

Not in CISA KEV

MEDIUM severity

Puma HTTP Request/Response Smuggling vulnerabilityGHSA-c2f4-cvqm-65w2

MEDIUMFix: puma/puma@5fc43d7

GHSA-c2f4-cvqm-65w2 is a medium-severity (CVSS 5.9) CWE-444 vulnerability in puma. A fix is available for puma — see the affected versions and patch details below.

Also known asCVE-2024-21647

Published

Jan 8, 2024

Updated

Sep 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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 GHSA-c2f4-cvqm-65w2.

EPSS Exploitation Probability

via FIRST.org ↗

1.0%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs62th percentile — riskier than 62% 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

2 pkgs affected

💎puma💎puma

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

Description

Impact

Prior to versions 6.4.2 and 5.6.8, puma exhibited dangerous behavior when parsing chunked transfer encoding bodies.

Fixed versions limit the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption.

Patches

The vulnerability has been fixed in 6.4.2 and 5.6.8.

Workarounds

No known workarounds.

References

HTTP Request Smuggling
Open an issue in Puma
See our security policy

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`puma`	≥ 6.0.0&&< 6.4.2	6.4.2`bundle update puma --conservative`
💎RubyGems	`puma`	all versions	5.6.8`bundle update puma --conservative`

Affected Products

1 product · 2 configurations

Application

pumapuma

≥ 6.0.0 && < 6.4.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for puma, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update puma to 6.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c2f4-cvqm-65w2 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 HatImportant

For Red Hat Satellite the affected version of the package tfm-rubygem-puma applies to EL7 only, which means it only applies to Satellite 6.11 on RHEL 7 which is currently out of support.

Product	Fixed in	Advisory
Red Hat Satellite 6.15 for RHEL 8	`rubygem-puma-0:6.4.2-1.el8sat`	RHSA-2024:2010

Frequently Asked Questions

### Impact Prior to versions 6.4.2 and 5.6.8, puma exhibited dangerous behavior when parsing chunked transfer encoding bodies. Fixed versions limit the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption. ### Patches The vulnerability has been fixed in 6.4.2 and 5.6.8. ### Workarounds No known workarounds. ### References * [HTTP Request Smuggling](https://portswigger.net/web-security/request-smuggling) * Open an issue in [Puma](https://github.com/puma/puma) * See our [security policy](https://github.com/puma/puma/