CVE-2026-84501 - CERT CVE
ID CVE-2026-84501
Sažetak 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.
Reference
CVSS
Base: 5.3
Impact: 1.4
Exploitability:3.9
Pristup
VektorSloženostAutentikacija
NETWORK LOW NONE
Impact
PovjerljivostCjelovitostDostupnost
NONE LOW NONE
CVSS vektor CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Zadnje važnije ažuriranje 18-09-2026 - 14:36
Objavljeno 16-09-2026 - 10:16