CVE-2026-105935: Apache Pulsar Functions Worker authorization bypass in trigger endpoint

CVE-2026-105935 · Severity: info · Published 2026-10-21

Apache Pulsar's Functions Worker REST API has a flaw in authorization checks when triggering functions. An authenticated user with permission to manage functions in a namespace can trick the Functions Worker into publishing messages to topics they don't have access to, including in other tenants. This allows bypassing publish restrictions, potentially poisoning data that other applications rely on.

Technologies: Apache Pulsar. Vendors: Apache.

Quick answers

Is CVE-2026-105935 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-105935 being exploited in the wild.
How severe is CVE-2026-105935?
Informational severity, published 21 October 2026.
Which products and versions are affected?
Apache Pulsar 2.0.0-rc1-incubating through 4.0.13 and 4.1.0 through 4.2.4.
Is there a fix for CVE-2026-105935?
Yes: fixed in Pulsar 4.0.14, 4.2.5. Until then: On versions 2.4.0 and later with authorization enabled, restrict the function-management permission to trusted roles only. On versions before 2.4.0, restrict REST API access to the Functions Worker to trusted callers. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-105935 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-105935?
Check whether you run Apache Pulsar at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Fixed in: Pulsar 4.0.14, 4.2.5

On versions 2.4.0 and later with authorization enabled, restrict the function-management permission to trusted roles only. On versions before 2.4.0, restrict REST API access to the Functions Worker to trusted callers.

Technical details

The trigger endpoint in Pulsar Functions Worker checks only that a caller is authorized to manage functions in a namespace, but does not verify that the caller is authorized to produce to the target input topic where the message is published. The message is published under the Functions Worker's broker-client identity (typically a superuser), allowing a low-privileged function manager to reach topics outside their namespace. Versions 2.0.0-rc1-incubating through 2.3.0 have no authorization check; 2.4.0 through the latest affected versions have incomplete checks. This requires the Functions Worker's own identity to have produce permissions on the target topic.

Affected products

  • Apache Pulsar 2.0.0-rc1-incubating through 4.0.13 and 4.1.0 through 4.2.4

Timeline

  • 2026-10-21: disclosed

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