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Medium 2 vendors · 2 advisories

CVE-2026-105927: Unauthorized message injection via missing dead letter topic permission check

CVE-2026-105927 key facts

CISA KEV
Not listed (catalogue checked )
Highest advisory rating
Medium
CVSS base score
5.4 (Red Hat), 2.3 (Apache)
Weakness
CWE-639
Fixed releases
  • Apache: 4.0.14, 4.2.5
  • Red Hat: 4.0.14, 4.2.5
Vendor advisories
2 from Apache, Red Hat
Listed by VulniPulse
Record changed

Ratings, versions and fixes are quoted from the vendor advisories that cover only CVE-2026-105927; each belongs to its advisory, not to every product listed. How records are collected and checked.

How do I fix CVE-2026-105927?

Upgrade to a fixed release named by the vendor:

  • Apache: 4.0.14, 4.2.5
  • Red Hat: 4.0.14, 4.2.5
  • 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. (Apache)
  • This issue affects Apache Pulsar versions from 2.3.0 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. (Apache)

Vendor advisories for CVE-2026-105927

Apache

1 advisory
  • Advisory severityLow2.3

    Low [CVE-2026-105927] Apache Pulsar: Improper authorization of WebSocket consumer dead letter topic allows writes without PRODUCE permission

    CVE-2026-105927Source published Source updated

    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…

    Affected products in this advisory
    • Apache Pulsar
    Source-reported affected versions
    • Apache Pulsar 2.3.0 before 4.0.14
    • Apache Pulsar 4.1.0 before 4.2.5
    Source-reported fixed versions
    • 4.0.14
    • 4.2.5
    Mitigation guidance
    • 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.
    • This issue affects Apache Pulsar versions from 2.3.0 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.
    Workarounds
    • Users who cannot upgrade immediately and do not require the WebSocket service should disable it.
    Full advisory and evidenceOpen source bulletin

Red Hat

1 advisory

References

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