CVE-2021-4221

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.43% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 36.9% of scored records. A rank, not a probability.

NVD base score

4.3 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2022-12-22 00:00Z3 YR AGO

Last updated

2025-04-16 15:49Z1 YR AGO

Reserved

2022-02-18

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Medium (CVSS 4.3)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Weaknesses

• CWE-1007Insufficient Visual Distinction of Homoglyphs Presented to UserBase

Data version

5.1

Document digest

f803509242f14cc7da9e49839fc7b38b226a77861a7acc96c8a764914f6bc07b

• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-38/
• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1704422