CVE-2024-21647: HTTP Request/Response Smuggling in puma
Description
Puma is a web server for Ruby/Rack applications built for parallelism. Prior to version 6.4.2, puma exhibited incorrect behavior when parsing chunked transfer encoding bodies in a way that allowed HTTP request smuggling. Fixed versions limits the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption. This vulnerability has been fixed in versions 6.4.2 and 5.6.8.
Classification
CVE ID: CVE-2024-21647
CVSS Base Severity: MEDIUM
CVSS Base Score: 5.9
CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Problem Types
CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')Affected Products
Vendor: puma
Product: puma
Exploit Prediction Scoring System (EPSS)
EPSS Score: 1.79% (probability of being exploited)
EPSS Percentile: 81.9% (scored less or equal to compared to others)
EPSS Date: 2025-06-29 (when was this score calculated)
Stakeholder-Specific Vulnerability Categorization (SSVC)
SSVC Exploitation: none
SSVC Technical Impact: partial
SSVC Automatable: false
References
https://nvd.nist.gov/vuln/detail/CVE-2024-21647https://github.com/puma/puma/security/advisories/GHSA-c2f4-cvqm-65w2
https://github.com/puma/puma/commit/5fc43d73b6ff193325e657a24ed76dec79133e93