CVE-2024-21647: 
Ruby vulnerability analysis and mitigation

CVE-2024-21647 affects Puma, 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, allowing HTTP request smuggling. The vulnerability was discovered and disclosed on January 8, 2024, affecting all versions before 6.4.2 and 5.6.8 (GHSA Advisory, NVD).

The vulnerability stems from incorrect parsing of chunked transfer encoding bodies in HTTP/1.1 requests. The issue specifically relates to unlimited chunk extensions processing. The vulnerability has been assigned a CVSS v3.1 base score of 7.5 (HIGH) by NIST with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, while GitHub assigned a score of 5.9 (MEDIUM) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (NVD).

Without size limits on chunk extensions, an attacker could cause unbounded resource consumption, specifically targeting CPU and network bandwidth. This could lead to a denial of service condition in affected systems (GHSA Advisory, Ubuntu Security).

The vulnerability has been fixed in Puma versions 6.4.2 and 5.6.8. The fix implements limits on the size of chunk extensions. No alternative workarounds are available, making upgrading to a patched version the only mitigation strategy (GHSA Advisory).