CVE-2026-105933
LowCVSS 2.3Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
Apache Pulsar allows administrators to enforce end-to-end message encryption for all topics in a namespace via the encryption_required namespace policy. If loading a persistent topic fails during initialization (e.g., metadata store read error or topic-level policy load failure), the broker logs a warning, disables the encryption requirement for that topic, and completes the topic load as successful. As a result, an authenticated client with produce permissions can publish unencrypted messages that the broker accepts and stores, even though the namespace policy requires encryption.
Risk Assessment
The organization may lose the end-to-end encryption guarantee for topics covered by the encryption_required policy, leading to storage of unencrypted sensitive data. The issue can recur on every topic load until the underlying initialization failure cause is resolved.
Recommendation
Upgrade Apache Pulsar to at least 4.0.14 (for 4.0.x) or 4.2.5 (for 4.1.x and 4.2.x). If immediate upgrade is not possible, monitor broker logs for warnings containing "isEncryptionRequired will be set to false", resolve the underlying failure cause, and reload the affected topic.
Other vulnerabilities in Apache Pulsar
See all- CVE-2026-105869Critical
A vulnerability in Apache Pulsar's MultiRolesTokenAuthorizationProvider allows a client to be authorized with all roles listed in an unverified JWT claim. When anonymousUserRole is set and authentication fails but falls back to anonymous, an unauthenticated client can send a forged or unsigned token with arbitrary roles and be authorized, potentially gaining super-user access.
- CVE-2026-105945High
The Apache Pulsar Packages Management Service with the FileSystemPackagesStorageProvider did not validate the version component of a package name, which could contain URL-encoded path separators and parent directory references. This allowed the filesystem storage provider to resolve the version to a location belonging to a package in a different tenant or namespace, and the containment check inside the storage directory did not prevent the access. An authenticated user with the packages permission on any namespace could download, overwrite or delete packages in other tenants or namespaces.
- CVE-2026-105942High
Apache Pulsar contains two flaws in the authorization of requests forwarded by a proxy on behalf of another user. The first authorizes the original principal using the proxy's authentication data (affecting e.g. MultiRolesTokenAuthorizationProvider), and the second skips the original principal check for tenant admin operations when the proxy role is a tenant admin. This may allow users to perform operations beyond their own permissions.
- CVE-2026-105938Low
Apache Pulsar did not apply subscription policies (Prefix subscription authentication mode or subscription permissions) in several admin REST API operations acting on subscriptions: clearing the backlog (for a named subscription and for all subscriptions), unsubscribe, and expiring messages for all subscriptions of a topic. An authenticated user with consume permission on the namespace or topic could bypass these policies and clear the backlog, expire messages, or delete a subscription that the policies would deny to that user.
- CVE-2026-105937High
A vulnerability in Apache Pulsar affects the shadow topics mechanism (PIP-180). The broker authorizes the caller only against the topic being created or updated, not against the source topic named in the PULSAR.SHADOW_SOURCE property. This allows an authenticated user with permission to create topics or update topic properties in one tenant to bind a topic to a source topic in another tenant and read its retained messages.
- CVE-2026-105936Medium
In Apache Pulsar, the functions connectors endpoint (/admin/v2/functions/connectors and /admin/v3/functions/connectors) returns the IO connector catalog without requiring super-user access, whereas the worker connectors endpoint enforces this check. As a result, any authenticated client can read the connector catalog metadata regardless of its role permissions. The issue affects versions from 2.4.1 before 4.0.14 and from 4.1.0 before 4.2.5.
- CVE-2026-105935Medium
The vulnerability affects the Apache Pulsar Functions Worker REST API trigger endpoint. The Worker publishes a message to the function's input topic using its own broker-client credentials rather than the caller's credentials, and does not verify that the caller is authorized to produce to that topic. Versions before 2.4.0 perform no caller authorization check for this endpoint at all.
- CVE-2026-105934High
Apache Pulsar broker versions 2.8.0 through 4.0.13 and 4.1.0 through 4.2.4 do not apply the tenant admin check to the caller for the truncate operation on a partitioned topic. Instead, the broker truncates each partition using its own internal admin client, so an authenticated user without tenant admin rights but with lookup permission can truncate any partitioned topic. This skips unacknowledged subscription backlog and permanently deletes older ledgers regardless of the namespace retention policy.
- CVE-2026-105932Low
The Apache Pulsar broker admin REST API endpoints for non-persistent topics (/admin/v2/non-persistent/.../entryFilters) do not perform the entry filters topic policy authorization check, unlike persistent topic endpoints. An authenticated user with produce or consume permission on a non-persistent topic can read, replace, or remove that topic's entry filter policy. This affects versions from 3.3.0 before 4.0.14 and from 4.1.0 before 4.2.5.
- CVE-2026-105931Low
The Apache Pulsar broker exposes a transaction administration REST API under /admin/v3/transactions. When authentication and authorization are enabled, most read endpoints of this API verify only that the request is authenticated and that the broker serves the requested topic or transaction coordinator, without checking whether the caller is permitted to access the tenant, namespace or topic whose data is returned. As a result, any authenticated user, including one with no permissions, can read transaction coordinator and transaction information belonging to other tenants.
Original NVD description (English source)
Apache Pulsar allows an administrator to require end-to-end message encryption for all topics in a namespace by setting the encryption_required namespace policy. When this policy is set, the broker rejects messages that are published without encryption. When the broker loads a persistent topic, it reads the namespace policies and the topic-level policies as part of topic initialization. If a step of this initialization fails, for example because of an error reading from the metadata store, a failure loading the topic-level policies or a failure in a later initialization step, the broker logs a warning, disables the encryption requirement for that topic, and completes the topic load as if it had succeeded. The topic is then served with encryption_required not enforced, even though the namespace policy requires it. Topic-level policies that could not be loaded are also not applied. While the encryption requirement is not enforced, an authenticated client with permission to produce to the affected topic can publish messages that are not encrypted, and the broker accepts and stores them. This applies both to producers created after the topic was loaded and to producers that were already connected. Messages published with encryption remain encrypted; the issue does not expose the content of encrypted messages or the encryption keys. The condition is not limited to transient failures. If the cause of the initialization failure persists, the encryption requirement is disabled again each time the topic is loaded, for example after a topic unload, a namespace bundle reassignment or a broker restart. An update to the namespace policies restores enforcement on a loaded topic, but only until the topic is loaded again. Enforcement is reliably restored only once the underlying cause of the failure has been resolved and the topic has been loaded again. The broker logs a warning when the encryption requirement is disabled, but the topic load is reported as successful and the state of the encryption requirement is not shown in the topic statistics. In fixed versions, a failure during topic initialization causes the topic load to fail so that it can be retried, instead of loading the topic with the encryption requirement disabled. This issue affects Apache Pulsar versions from 1.22.0-incubating before 4.0.14 and from 4.1.0 before 4.2.5. - 4.0.x version users should upgrade to at least 4.0.14. - 4.1.x and 4.2.x version users should upgrade to at least 4.2.5. Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions. The currently supported Apache Pulsar release lines are 4.0.x and 5.0.x. The supported versions schedule is available at https://pulsar.apache.org/contribute/release-policy/. Users who rely on encryption_required and cannot upgrade immediately can monitor the broker logs for warnings containing "isEncryptionRequired will be set to false" (the exact wording of the message differs between releases), resolve the underlying cause of the failure, and then reload the affected topic and confirm that the warning does not recur.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS