CVE-2026-105937

published 2026-10-21

CVE-2026-105937: Apache Pulsar shadow topics (PIP-180) are topics that read the stored messages of a source topic from that topic's managed ledger. The source topic is selected…

Priority P3 57 high 8.7 CVSS 4.0

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Apache Pulsar shadow topics (PIP-180) are topics that read the stored messages of a source topic from that topic's managed ledger. The source topic is selected by setting the reserved topic property PULSAR.SHADOW_SOURCE. The admin REST API accepts this property when creating a non-partitioned or partitioned topic and when updating the properties of an existing topic. On these paths the broker authorizes the caller only against the topic being created or updated. It does not authorize the caller against the source topic named in the property. The existing authorization for shadow topic configuration (the SHADOW_TOPIC topic policy on the source topic) is applied only to the source-side shadow topics admin API, not to these paths.

As a result, an authenticated user who is allowed to create topics or update topic properties in one tenant can bind a topic in that tenant to a persistent topic in any other tenant. With the default authorization provider, these operations require the tenant admin role for the user's own tenant. The user does not need any permission on the source topic, its namespace or its tenant. This impact analysis assumes that Pulsar has been configured with the default authorization provider. For custom authorization providers, the impact could be different.

The user can then consume from the shadow topic, using only permissions on their own topic, and receive retained messages that were published to the source topic in the other tenant. Exposure is limited to messages that are still retained and readable in the source topic's ledgers; messages protected with client-side end-to-end encryption cannot be decrypted without the encryption keys. A producer on the shadow topic can also register a new schema version under the source topic's schema, subject to the schema compatibility settings; existing schema versions are not replaced.

In addition, the shadow topic's managed ledger applies its own retention, trimming, offloading and deletion to the source

Affected

2 ranges

Vendor	Product	Version range	Fixed in
apache_software_foundation	apache_pulsar	>= 3.0.0 < 4.0.14	4.0.14
apache_software_foundation	apache_pulsar	>= 4.1.0 < 4.2.5	4.2.5

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CWE-862