CVE-2026-25742: Zulip: Anonymous File Access After Disabling Spectator Access
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 (enablespectatoraccess / WEBPUBLICSTREAMSENABLED) 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/<streamid>/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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Zulipto a version that resolves this vulnerability.Fixed in 11.6
Event History
Frequently Asked Questions
What is the severity of CVE-2026-25742?
CVE-2026-25742 is classified as a medium severity vulnerability.
How do I fix CVE-2026-25742?
To remediate CVE-2026-25742, users should upgrade Zulip to version 11.6 or later.
What does CVE-2026-25742 affect?
CVE-2026-25742 affects Zulip versions from 1.4.0 to before 11.6.
What is the nature of the vulnerability in CVE-2026-25742?
CVE-2026-25742 allows anonymous file access even after disabling spectator access.
Who is impacted by CVE-2026-25742?
Organizations using vulnerable versions of Zulip are impacted by CVE-2026-25742.