CVE-2026-25742
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk23th percentile - higher than 23% of all known CVEs
Summary
In Zulip before version 11.6, even after disabling spectator access, attachments from web-public streams remained anonymously accessible. Additionally, the /users/me/<stream_id>/topics endpoint remained reachable anonymously, allowing retrieval of topic history for those streams.
Risk Assessment
The organization risks unauthorized access to files and topic history that should be protected after disabling public access.
Recommendation
Update Zulip to version 11.6 or later, which contains the fix.
Original NVD description (English source)
Zulip is an open-source team collaboration tool. Prior to version 11.6, Zulip is an open-source team collaboration tool. From version 1.4.0 to before version 11.6, even after spectator access (enable_spectator_access / WEB_PUBLIC_STREAMS_ENABLED) is disabled, attachments originating from web-public streams can still be retrieved anonymously. As a result, file contents remain accessible even after public access is intended to be disabled. Similarly, even after spectator access is disabled, the /users/me/<stream_id>/topics endpoint remains reachable anonymously, allowing retrieval of topic history for web-public streams. This issue has been patched in version 11.6. This issue has been patched in version 11.6.