When SASL authentication is enabled on the client port, the server's SASL callback handler grants every authorization identity (authzid) that a client requests, without checking it against the principal the client authenticated as. The server then tries to replace the requested identity with a canonical form of the authenticated principal, derived from the zookeeper.security.auth_to_local rules. If no rule applies to the principal, canonicalization fails and the error is only logged. The client-requested authzid then becomes the session's SASL identity for all ACL checks.
An authenticated client whose principal is not covered by the auth_to_local rules can therefore claim any SASL identity. With the default rules, this includes any Kerberos principal from a realm other than the server's default realm, such as a principal from a cross-realm trusted realm. The client then gets the permissions granted to that identity in sasl ACLs. If the requested identity matches a configured zookeeper.superUser, it gets superuser access to the whole data tree.
Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Apache Software Foundation | Apache ZooKeeper | unaffected |
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Wed, 04 Nov 2026 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Improper Authorization vulnerability in Apache ZooKeeper. When SASL authentication is enabled on the client port, the server's SASL callback handler grants every authorization identity (authzid) that a client requests, without checking it against the principal the client authenticated as. The server then tries to replace the requested identity with a canonical form of the authenticated principal, derived from the zookeeper.security.auth_to_local rules. If no rule applies to the principal, canonicalization fails and the error is only logged. The client-requested authzid then becomes the session's SASL identity for all ACL checks. An authenticated client whose principal is not covered by the auth_to_local rules can therefore claim any SASL identity. With the default rules, this includes any Kerberos principal from a realm other than the server's default realm, such as a principal from a cross-realm trusted realm. The client then gets the permissions granted to that identity in sasl ACLs. If the requested identity matches a configured zookeeper.superUser, it gets superuser access to the whole data tree. Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue. | |
| Title | Apache ZooKeeper: SASL authorization bypass on the client port through a client-supplied authorization ID | |
| Weaknesses | CWE-863 | |
| References |
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| Metrics |
cvssV4_0
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MITRE
Status: PUBLISHED
Assigner: apache
Published:
Updated: 2026-11-04T11:09:10.129Z
Reserved: 2026-09-25T16:45:48.869Z
Link: CVE-2026-100252
Vulnrichment
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NVD
Status : Received
Published: 2026-11-04T11:17:06.717
Modified: 2026-11-04T11:17:06.717
Link: CVE-2026-100252
Redhat
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OpenCVE Enrichment
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