Improper Authorization Vulnerability in Apache ZooKeeper by Apache
CVE-2026-100252

8.6HIGH

Key Information:

Vendor

Apache
Status
Apache Zookeeper
Vendor
CVE Published:
4 November 2026

What is CVE-2026-100252?

An improper authorization issue exists in Apache ZooKeeper where SASL authentication on the client port allows any requested authorization identity. Without proper validation against the authenticated principal, the server substitutes the requested identity with a canonical form but fails if no applicable rule is configured, leading to permission grants not intended for the client. This exposes a significant security risk, as an authenticated client can exploit this vulnerability to claim unauthorized identities and potentially gain superuser access depending on configured ACLs. It is crucial for users to upgrade to versions 3.8.8 or 3.9.7 to mitigate this risk.

Affected Version(s)

Apache ZooKeeper 3.9.0 <= 3.9.6

Apache ZooKeeper 3.8.0 <= 3.8.7

References

https://lists.apache.org/thread.html/81rdyqlmlp3dtkkqgp8t...
vendor-advisory

CVSS V4

Score:
8.6
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

cunyi li <xiaoheihei1107@gmail.com>
Prasath Jayasundar & PayPal Cyber Security Team
.