CVE intelligence and bounded remediation

CVE-2022-24790 — Puma is a simple, fast, multi-threaded, parallel HTTP 1.1 server for Ruby/Rack applications

Critical CVSS 9.1

Puma is a simple, fast, multi-threaded, parallel HTTP 1.1 server for Ruby/Rack applications. When using Puma behind a proxy that does not properly validate that the incoming HTTP request matches the RFC7230 standard, Puma and the frontend proxy may disagree on where a request starts and ends. This would allow requests to be smuggled via the front-end proxy to Puma. The vulnerability has been fixed in 5.6.4 and 4.3.12. Users are advised to upgrade as soon as possible. Workaround: when deploying a proxy in front of Puma, turning on any and all functionality to make sure that the request matches the RFC7230 standard.

Severity
Critical
CVSS
9.1 (3.1)
Published
2022-03-30
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-444

Affected products

  • puma / puma
  • debian / debian_linux / 10.0
  • debian / debian_linux / 11.0
  • fedoraproject / fedora / 35
  • fedoraproject / fedora / 36
  • fedoraproject / fedora / 37

Showing 6 representative product identities from 7 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

HTTP request smuggling and message-boundary ambiguity

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Check exposure

  • Inventory every proxy, CDN, gateway, load balancer, service mesh, and application server hop on affected request paths.
  • Compare documented parsing and normalization behavior for message length, transfer coding, duplicate headers, and protocol translation.
  • Identify connection reuse and which downstream services trust headers added by intermediaries.

Remediate safely

  • Update affected intermediaries and origin servers and align them on a single standards-compliant request framing policy.
  • Reject ambiguous length, transfer-coding, duplicate, malformed, and unsupported framing before forwarding.
  • Normalize or remove hop-by-hop and identity headers at one controlled boundary and add multi-hop regression tests.

Authoritative sources

Complete CVE record and remediation plan

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