CVE-2026-40021

216.73.216.89

· Published 10/04/2026 16:16 · Modified 10/04/2026 17:17

Labels: CVE-2026-40021 2026-04-10 CVE-2026-40021 CWE-116 [email protected]

Essential information

Published: 10/04/2026 16:16
Modified: 10/04/2026 17:17
Author: —
Creator: —
CVSS: 6.3 MEDIUM (v3) 6.3 MEDIUM (v4.0)
CISA KEV: No
CWE: —
CVSS vector: —

CVSS metrics

Description

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.

NVD status

Status: Received — CVE has been recently published to the CVE List and has been received by the NVD.
Source: [email protected]
NVD: View on NVD

Affected products (CPE)

Product	CPE
apache / log4net	`cpe:2.3:a:apache:log4net:<3.3.0:::::::*`