CVE-2026-25742 Zulip: Anonymous File Access After Disabling Spectator Access
Attackers can anonymously access files and topic history from web-public streams even after disabling spectator access, exposing sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-25742?
CVE-2026-25742 is a medium-severity missing authorization vulnerability in zulip, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-862
Which versions are affected by CVE-2026-25742?
It affects 1 product.
Products include Zulip Zulip.
How do I fix CVE-2026-25742?
No fix has been published for CVE-2026-25742 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-25742 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25742 exists.
Other vulnerabilities in zulip
- CVE-2021-43799 RabbitMQ exposes ports with weak default secrets in Zulip Server
- CVE-2022-35962 Crafted link in Zulip message can cause disclosure of credentials
- CVE-2016-4427 Auth bypass in zulip
- CVE-2021-3866 Cross-site Scripting (XSS) - Stored in zulip/zulip
- CVE-2023-28623 Unauthorized user can register an account in specific configurations in Zulip
Sources
Also known as GHSA-f47p-xjqq-g28w.