CVE-2023-33186: 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 product...

Description

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.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

0.62%

45.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Zulip	Zulip Server	7.0	Beta1

References

Timeline

Published: May 30, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-33186?

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.

How severe is CVE-2023-33186?

CVE-2023-33186 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.62% probability of exploitation in the next 30 days.

How do I fix CVE-2023-33186?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.