How severe is CVE-2021-43221?

CVE-2021-43221 has a CVSS 3.x base score of 4.2, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-43221 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43221?

CVE-2021-43221 affects Microsoft Edge Chromium. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43221?

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

When was CVE-2021-43221 published?

CVE-2021-43221 was published on 2021-11-24 and last updated on 2026-06-17.

CVE-2021-43221

CVE-2021-43221 is a medium-severity vulnerability in Microsoft Edge Chromium with a CVSS 3.x base score of 4.2. 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-94.

Key facts

Severity: Medium (CVSS 3.x base score 4.2)
CVSS v2: 4.0
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Microsoft Edge Chromium
Published: 2021-11-24
Last modified: 2026-06-17

Description

Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-43221?: Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability
How severe is CVE-2021-43221?: CVE-2021-43221 has a CVSS 3.x base score of 4.2, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-43221 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43221?: CVE-2021-43221 affects Microsoft Edge Chromium. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43221?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43221 published?: CVE-2021-43221 was published on 2021-11-24 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43221

Affected products (1)

cpe:2.3:a:microsoft:edge_chromium:*:*:*:*:*:*:*:*

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