CVE-2026-47736

HIGH

Puma PROXY Protocol v1 Parser Allows Remote Memory Exhaustion

Title source: cna
STIX 2.1

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.

References (5)

Core 5

Scores

CVSS v3 7.5
EPSS 0.0035
EPSS Percentile 27.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-400
Status published
Products (2)
puma/puma >= 5.5.0, < 7.2.1
puma/puma >= 8.0.0, < 8.0.2
Published Jul 14, 2026
Tracked Since Jul 15, 2026