7.5

CVE-2026-59739: apache software foundation apache zookeeper Missing Authorization

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-59739DEBIAN-CVE-2026-59739
Published 16-09-2026Last modified 17-09-2026
Open JSON

Vulnerability summary

CVE-2026-59739 is a high (CVSS 7.5) Missing Authorization vulnerability in apache software foundation apache zookeeper. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 44.9% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.55%
0%100%
Low · +0.12 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 16-09-2026
    PublishedVulnerability first disclosed.
  2. 17-09-2026
    Last modifiedVulnerability information updated.

Description

Information disclosure via SetWatches reconnect replay in Apache ZooKeeper due to missing ACL check. An attacker can discover ACL-restricted paths by registering exists-watches on non-existent paths, then reconnecting after the paths are created with restricted ACLs. Issue is caused by incomplete fix for CVE-2024-23944 (ZOOKEEPER-4799). The fix added ACL checking to WatchManager.triggerWatch(). However, DataTree.setWatches() — the SetWatches/SetWatches2 reconnect replay handler — still calls watcher.process(event) with null ACL, bypassing the check entirely. It's important to note that only the path is exposed by this vulnerability, not the data of znode, but since znode path can contain sensitive information like user name or login ID, this issue is potentially critical. Users are recommended to upgrade to version 3.9.6, 3.8.7 which fixes the issue.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.55%

Chance of exploitation in the next 30 days

Percentile

45%

Versus all other CVEs

30-day change

+0.12 pp

From 0.44% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.55%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Apache1 product
  • zookeeper≥ 3.8.0, < 3.8.7 | ≥ 3.9.0, < 3.9.6
Apache software foundation1 product
Debian1 product
  • zookeeperAll versions (No fix recorded) | < 3.9.6-1
Ubuntu1 product
  • zookeeperAll versions (No fix recorded)

4 vendors · 4 products

References

4 links