CVE-2017-0881 Missing authorization in Zulip Server Versions 1.4.2 and below
Authenticated users can bypass invitation requirements to subscribe to private streams, exposing private data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2017-0881?
CVE-2017-0881 is a medium-severity missing authorization vulnerability in Zulip Server Versions 1.4.2 and below, published on 28 Mar 2017. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An error in the implementation of an autosubscribe feature in the check_stream_exists route of the Zulip group chat application server before 1.4.3 allowed an authenticated user to subscribe to a private stream that should have required an invitation from an existing member to join. The issue affects all previously released versions of the Zulip server.
Which versions are affected by CVE-2017-0881?
It affects 1 product.
Products include Zulip Zulip Server.
How do I fix CVE-2017-0881?
No fix has been published for CVE-2017-0881 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-2017-0881 being exploited?
There is no known exploitation of CVE-2017-0881 in the wild and no public exploit code.
Other vulnerabilities in Zulip Server Versions 1.4.2 and below
- CVE-2019-18933 Information disclosure in n/a
- CVE-2020-15070 Code injection in n/a
- CVE-2017-0910 Missing authorization in Zulip Server
- CVE-2025-31478 Zulip Authentication Backend Configuration Bypass
- CVE-2023-33186 Cross-site scripting vulnerability in Zulip Server development branch via topic tooltip
Sources
Also known as GHSA-435h-5vch-xh86.