Detections
Analytics

SCA: security update for log4net (GHSA-4f7c-pmjv-c25w)

medium Tenable Cloud Security Plugin ID 440340

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.html#layout-
 list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.html#layout-
 list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0 specification
 https://www.w3.org/TR/xml/#charsets in MDC property keys and values, as well as the identity field that
 may carry attacker-influenced data. This causes an exception during serialization and the silent loss of
 the affected log event. An attacker who can influence any of these fields can exploit this to suppress
 individual log records, impairing audit trails and detection of malicious activity. Users are advised to
 upgrade to Apache Log4net 3.3.0, which fixes this issue. (CVE-2026-40021)

Solution

Update the log4net library and its related packages to version 3.3.0 or later.

See Also

https://github.com/advisories/GHSA-4f7c-pmjv-c25w

Plugin Details

Severity: Medium

ID: 440340

Version: Revision 1.8

Type: Local

Family: SCA Checks

Published: 4/14/2026

Updated: 6/1/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 3.2

Percentile: 51.15

Vendor

Vendor Severity: Medium

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2026-40021

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

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

CVSS v4

Risk Factor: Medium

Base Score: 6.3

Threat Score: 1.7

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 4/10/2026

Vulnerability Publication Date: 4/10/2026

Reference Information

CVE: CVE-2026-40021

cwe: CWE-116