CVE-2021-40663
CVSS v3
9.8
CRITICAL
EPSS Score
1.8 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
deep.assign npm package 0.0.0-alpha.0 is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Technical details
- Published
- 2022-06-30
Frequently asked questions
What is CVE-2021-40663?
deep.assign npm package 0.0.0-alpha.0 is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Is CVE-2021-40663 actively exploited?
Active exploitation of CVE-2021-40663 has not been confirmed. Its EPSS score was 1.8% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-40663?
CVE-2021-40663 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2021-40663 affecting your environment?
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