Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
puma puma affected
Version Status Constraints
>= 5.5.0, < 7.2.1 affected —
>= 8.0.0, < 8.0.2 affected —

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Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-qpgp-93vx-g8v8 Puma PROXY Protocol v1 Parser Allows Remote Memory Exhaustion
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f cve-icon
https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58 cve-icon
https://github.com/puma/puma/releases/tag/v7.2.1 cve-icon
https://github.com/puma/puma/releases/tag/v8.0.2 cve-icon
https://github.com/puma/puma/security/advisories/GHSA-qpgp-93vx-g8v8 cve-icon
History

Tue, 14 Jul 2026 20:00:00 +0000

Type Values Removed Values Added
Description Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.
Title Puma PROXY Protocol v1 Parser Allows Remote Memory Exhaustion
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-14T19:54:26.229Z

Reserved: 2026-05-19T22:16:39.503Z

Link: CVE-2026-47736

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses