Puma HTTP Request/Response Smuggling vulnerability

CVE-2024-21647 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2024-01-08 15:56:48 UTC
Updated
2025-11-04 16:49:09 UTC
GitHub reviewed
2024-01-08 15:56:48 UTC
NVD published
2024-01-08

EPSS Score

Score Percentile
2.46% 85.00%

CVSS Scores

Base score Version Severity Vector
5.9 3.1 —
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-c2f4-cvqm-65w2 ↗
CVE CVE-2024-21647 ↗

CWEs

CWE id Name
CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Credits

  • bartekn (reporter)

Affected packages (2)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
rubygems puma >= 6.0.0, < 6.4.2 6.4.2 —
rubygems puma < 5.6.8 5.6.8 —

References

cvelogic Threat Intelligence