Debian dla-4826 : puma - security update

high Nessus Plugin ID 363861

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 12 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-4826 advisory.

- ------------------------------------------------------------------------- Debian LTS Advisory DLA-4826-1 [email protected] https://www.debian.org/lts/security/ Abhijith PA October 07, 2026 https://wiki.debian.org/LTS
- -------------------------------------------------------------------------

Package : puma Version : 5.6.5-3+deb12u2 CVE ID : CVE-2026-47736 CVE-2026-47737

Two vulnerabilities were discovered in Puma, a simple, fast, threaded, and highly concurrent server for Ruby/Rack applications

CVE-2026-47736

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.

CVE-2026-47737

Puma is vulnerable to source IP spoofing when set_remote_address proxy_protocol: :v1 is enabled and persistent connections are used because Puma incorrectly re-parses PROXY protocol headers after each keep-alive request on the same connection, allowing an attacker to inject a second PROXY header and overwrite REMOTE_ADDR.

For Debian 12 bookworm, these problems have been fixed in version 5.6.5-3+deb12u2.

We recommend that you upgrade your puma packages.

For the detailed security status of puma please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/puma

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade the puma packages.

Plugin Details

Severity: High

ID: 363861

File Name: debian_DLA-4826.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Debian Local Security Checks

Published: 10/7/2026

Updated: 10/7/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.77

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N

CVSS Score Source: CVE-2026-47737

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:12.0, p-cpe:/a:debian:debian_linux:puma

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 10/7/2026

Vulnerability Publication Date: 6/8/2026

Reference Information

CVE: CVE-2026-47736, CVE-2026-47737

Detections

Analytics