Skip to content
Fencer Intel
critical 9.8

CVE-2021-33907 json

The Zoom Client for Meetings for Windows in all versions before 5.3.0 fails to properly validate the certificate information used to sign .…

published 5y ago modified 4mo ago also EUVD-2021-20579

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.0%
EPSS 4.0% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

The Zoom Client for Meetings for Windows in all versions before 5.3.0 fails to properly validate the certificate information used to sign .msi files when performing an update of the client. This could lead to remote code execution in an elevated privileged context.

Patch / fix

  • zoom meetings 5.3.0

Is CVE-2021-33907 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

4.01% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • n/a Zoom Client for Meetings for Windows

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.