CVE-2026-105927
The Apache Pulsar WebSocket service allows a WebSocket consumer to configure a dead letter policy through query parameters of the consumer endpoint, including the deadLetterTopic parameter that nam…
Overview
CVE-2026-105927 is a known-severity vulnerability. It was published on October 21, 2026.
Technical description
The Apache Pulsar WebSocket service allows a WebSocket consumer to configure a dead letter policy through query parameters of the consumer endpoint, including the deadLetterTopic parameter that names the topic to which messages are written after the maximum number of redeliveries is exceeded. When authorization is enabled, the WebSocket service checks only that the connecting user holds the CONSUME permission on the subscribed topic. It does not check whether the user holds the PRODUCE permission on the topic named in deadLetterTopic. The dead letter messages are then written by the WebSocket service using its own broker client identity rather than the identity of the connecting user.
As a result, an authenticated user who holds the CONSUME permission on at least one topic can cause messages to be written to a topic of their choosing in any existing namespace, including namespaces belonging to other tenants, provided the role used by the WebSocket service to connect to the brokers is
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-105927?
CVE-2026-105927 is a known-severity vulnerability. It was published on October 21, 2026.
How severe is CVE-2026-105927?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-105927?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-105927?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-105927 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.