CVE-2023-33186
HighCVSS 8.2Exploitation Probability (EPSS)
Low risk45th percentile - higher than 45% of all known CVEs
Summary
Zulip, a team collaboration tool, has a cross-site scripting (XSS) vulnerability in tooltips on the message feed. An attacker can craft a malicious topic for a message that, when hovered over by a victim, executes JavaScript code controlled by the attacker.
Risk Assessment
This vulnerability could lead to the execution of malicious code in the victim's browser, posing risks such as data theft or session hijacking. Organizations using Zulip should be aware of the potential threats associated with this flaw.
Recommendation
It is recommended to update Zulip Server to the latest version to mitigate this vulnerability. Additionally, implementing security measures such as message content filtering is advisable.
Other vulnerabilities in Zulip Server
See all- CVE-2017-0910High
In Zulip Server before 1.7.1, a vulnerability in the invitation system allows an authorized user from one realm on the server to create a user account in any other realm.
- CVE-2026-102893Critical
Zulip Server through 12.1 has a vulnerability in GenericOpenIdConnectBackend that does not reject an explicitly false email_verified claim, allowing login to an existing account if a misconfigured trusted identity provider returns an email address not controlled by the user.
- CVE-2026-100404Medium
Zulip Server versions through 12.1 allow guest users to receive new message events for public channels outside their subscriptions. A guest can register an event queue requesting messages from an unsubscribed public channel, or an existing queue can remain affected after access is removed, disclosing new public-channel messages to the guest.
Original NVD description (English source)
Zulip is an open-source team collaboration tool with unique topic-based threading that combines the best of email and chat to make remote work productive and delightful. The main development branch of Zulip Server from May 2, 2023 and later, including beta versions 7.0-beta1 and 7.0-beta2, is vulnerable to a cross-site scripting vulnerability in tooltips on the message feed. An attacker who can send messages could maliciously craft a topic for the message, such that a victim who hovers the tooltip for that topic in their message feed triggers execution of JavaScript code controlled by the attacker.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS