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.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
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| Apache Software Foundation | Apache ZooKeeper | unaffected |
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Wed, 04 Nov 2026 12:30:00 +0000
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Wed, 04 Nov 2026 11:00:00 +0000
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| 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 | |
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| Metrics |
cvssV4_0
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Subscriptions
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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
No data.
NVD
Status : Received
Published: 2026-11-04T11:17:06.717
Modified: 2026-11-04T12:17:05.033
Link: CVE-2026-100252
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-11-04T12:30:10Z