How severe is CVE-2021-34420?

CVE-2021-34420 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-34420 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34420?

CVE-2021-34420 affects Zoom Zoom Client For Meetings. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34420?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-34420 published?

CVE-2021-34420 was published on 2021-11-11 and last updated on 2026-06-17.

CVE-2021-34420

CVE-2021-34420 is a medium-severity vulnerability in Zoom Zoom Client For Meetings with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
CVSS v2: 4.3
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Zoom Zoom Client For Meetings
Published: 2021-11-11
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-34420?: 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.
How severe is CVE-2021-34420?: CVE-2021-34420 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-34420 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34420?: CVE-2021-34420 affects Zoom Zoom Client For Meetings. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34420?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-34420 published?: CVE-2021-34420 was published on 2021-11-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:zoom:zoom_client_for_meetings:*:*:*:*:*:windows:*:*

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