Missing Authorization in Apache ZooKeeper - CVE-2026-59739
Published: September 16, 2026
Vulnerability identifier: #VU150217
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59739
CWE-ID: CWE-862
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose ACL-restricted znode paths.
The vulnerability exists due to a missing authorization check in the DataTree.setWatches() SetWatches/SetWatches2 reconnect replay handler when replaying registered exists-watches after a client reconnects. A remote attacker can register exists-watches on non-existent paths and reconnect after the paths are created with restricted ACLs to disclose ACL-restricted znode paths.
Only znode paths are exposed; znode data is not exposed.
Affected software
Apache ZooKeeper
How to mitigate CVE-2026-59739
Install security update from vendor's website.
Apache ZooKeeper - addressed in versions 3.8.7, 3.9.6