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Apache Tomcat 9.0.40 < 9.0.117 Improper Encoding or Escaping of Output Vulnerability (CVE-2026-34483)

high Nessus Plugin ID 334514

Synopsis

The remote Apache Tomcat server is affected by an improper encoding or escaping of output vulnerability

Description

The version of Tomcat installed on the remote host is 9.0.40 prior to 9.0.117. It is, therefore, affected by a vulnerability as referenced in the fixed_in_apache_tomcat_9.0.117_security-9 advisory.

 - Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue. (CVE-2026-34483)

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

Solution

Upgrade to Apache Tomcat version 9.0.117 or later.

See Also

http://www.nessus.org/u?66d56d5e

http://www.nessus.org/u?d958092b

Plugin Details

Severity: High

ID: 334514

File Name: tomcat_9_0_117_cve-2026-34483.nasl

Version: 1.1

Type: Combined

Agent: windows, macosx, unix

Family: Web Servers

Published: 8/11/2026

Updated: 8/11/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.76

CVSS v2

Risk Factor: High

Base Score: 7.8

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

CVSS Score Source: CVE-2026-34483

CVSS v3

Risk Factor: High

Base Score: 7.5

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

Vulnerability Information

CPE: cpe:/a:apache:tomcat:9

Required KB Items: installed_sw/Apache Tomcat

Patch Publication Date: 4/3/2026

Vulnerability Publication Date: 4/4/2026

Reference Information

CVE: CVE-2026-34483