CVE-2026-84501: Apache ZooKeeper: Operational log forgery via newline injection in EnsembleAuthenticationProvider
Unauthenticated attackers can forge Apache ZooKeeper operational log lines via newline injection in crafted ensemble authentication requests.
CVE-2026-84501 (moderate severity) affects Apache ZooKeeper 3.9.0-3.9.5 and 3.8.0-3.8.6. An unauthenticated attacker can inject arbitrary fake log lines into the operational log by sending a crafted add_auth("ensemble", ...) request containing newline characters. The forged entries could mislead operators or corrupt log-based monitoring and forensics.
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