Linux Distros Unpatched Vulnerability : CVE-2026-34831

medium Nessus Plugin ID 304827

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail sets the Content-Length response header using String#size instead of String#bytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters.
This results in incorrect HTTP response framing and may cause response desynchronization in deployments that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6. (CVE-2026-34831)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 304827

File Name: unpatched_CVE_2026_34831.nasl

Version: 1.11

Type: Local

Agent: unix

Family: Misc.

Published: 4/4/2026

Updated: 4/23/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.3

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.4

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

CVSS Score Source: CVE-2026-34831

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 6

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

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

Vulnerability Information

CPE: cpe:/o:centos:centos:7, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:centos:centos:pcs, p-cpe:/a:centos:centos:pcs-snmp, p-cpe:/a:redhat:enterprise_linux:pcs, p-cpe:/a:centos:centos:cockpit-ha-cluster, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:cockpit-ha-cluster, p-cpe:/a:redhat:enterprise_linux:pcs-snmp, cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:debian:debian_linux:ruby-rack, cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:python-clufter, p-cpe:/a:redhat:enterprise_linux:python-clufter, cpe:/o:debian:debian_linux:12.0, cpe:/o:redhat:enterprise_linux:10, cpe:/o:debian:debian_linux:13.0

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 4/2/2026

Reference Information

CVE: CVE-2026-34831

Detections

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