CVE-2026-105938

published 2026-10-21

CVE-2026-105938: Apache Pulsar namespaces can restrict which roles may use a subscription, either with the Prefix subscription authentication mode, which requires a…

Priority P4 21 low 2.3 CVSS 4.0

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Apache Pulsar namespaces can restrict which roles may use a subscription, either with the Prefix subscription authentication mode, which requires a subscription name to start with the role name, or by granting permission on a subscription to specific roles. Topic-level subscription operations, such as consuming, skipping messages, resetting a cursor or deleting a subscription, apply these subscription policies. Several admin REST API operations that act on subscriptions did not apply them:

- the namespace-level and bundle-level clear backlog operations, both for a named subscription and for all subscriptions;
- the namespace-level and bundle-level unsubscribe operations;
- the topic-level operation that expires messages for all subscriptions of a topic.

With the default authorization provider, the namespace-level operations require only consume permission granted on the namespace, and the expire-all operation requires only consume permission on the topic. As a result, when authentication and authorization are enabled and a namespace uses the Prefix subscription authentication mode or subscription permissions, an authenticated user with such consume permission can clear the backlog of, expire messages of, or delete a subscription that the policies would deny to that user. Tenant admin or superuser access is not required. The clear backlog operations can also be applied to the cursors used for geo-replication, so that messages not yet replicated to a remote cluster are skipped. Deployments that do not configure the Prefix subscription authentication mode or subscription permissions (the defaults) are not affected by this bypass, because consume permission on the namespace or topic already allows these operations there. This impact analysis assumes that Pulsar has been configured with the default authorization provider. For custom authorization providers, the impact could be different.

The impact is on the integrity of subscription state. Clearing or expiring the ba

Affected

2 ranges

Vendor	Product	Version range	Fixed in
apache_software_foundation	apache_pulsar	>= 2.8.0 < 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-863