Improper Output Neutralization for Logs Affecting org.apache.zookeeper:zookeeper package, versions [3.8.0,3.8.7)[3.9.0,3.9.6)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Improper Output Neutralization for Logs vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-JAVA-ORGAPACHEZOOKEEPER-20159005
- published27 Sept 2026
- disclosed16 Sept 2026
- creditYoulong Chen Institute of Computing Technology
Introduced: 16 Sep 2026
NewCVE-2026-84439 (opens in a new tab)How to fix?
Upgrade org.apache.zookeeper:zookeeper to version 3.8.7, 3.9.6 or higher.
Overview
org.apache.zookeeper:zookeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.
Affected versions of this package are vulnerable to Improper Output Neutralization for Logs in the audit logging. An attacker can manipulate audit log entries by injecting tab characters into the username or digest ACL id fields, which are then interpreted as field separators in the tab-separated key=value log format. This allows the attacker to forge log fields, spoof operation types, and corrupt forensic evidence by sending specially crafted authentication or setACL requests when audit logging is enabled.