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CVE-2026-84501 (GCVE-0-2026-84501)

Vulnerability from cvelistv5 – Published: 2026-09-16 09:28 – Updated: 2026-09-16 10:12
VLAI
Title
Apache ZooKeeper: Operational log forgery via newline injection in EnsembleAuthenticationProvider
Summary
An unauthenticated attacker can inject arbitrary fake log lines into Apache ZooKeeper's operational log by sending a crafted add_auth("ensemble", ...) request containing newline characters (\n). When the ensemble name doesn't match, EnsembleAuthenticationProvider.handleAuthentication() logs the raw, unsanitized name via LOG.warn(). Because SLF4J's {} placeholder preserves embedded newlines, the attacker can forge complete log entries — with arbitrary timestamps, log levels, class names, and messages — that are visually indistinguishable from genuine ZooKeeper log output. This issue affects Apache ZooKeeper: from 3.9.0 through 3.9.5, from 3.8.0 through 3.8.6. Users are recommended to upgrade to version 3.8.7 or 3.9.6, which fixes the issue.
Severity
No CVSS data available.
CWE
  • CWE-117 - Improper output neutralization for logs
Impacted products
Vendor Product Version CPE status
Apache Software Foundation Apache ZooKeeper Affected: 3.9.0 , ≤ 3.9.5 (maven)
Affected: 3.8.0 , ≤ 3.8.6 (maven)
guessed Create a notification for this product.
Show details on NVD website

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