CVE-2026-40021

01/תיאור (מקור, אנגלית)

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.

02/מוצרים מושפעים

apache: log4net

03/קישורים6

• lists.apache.org/thread/q8otftjswhk69n3kxslqg7cobr0x4st7 Mailing ListVendor Advisory
• logging.apache.org/security.html#CVE-2026-40021 Vendor Advisory
• github.com/apache/logging-log4net/pull/280 Issue Tracking
• logging.apache.org/cyclonedx/vdr.xml Product
• logging.apache.org/log4net/manual/configuration/layouts.html Product
• www.openwall.com/lists/oss-security/2026/04/10/11 Mailing ListThird Party Advisory