CVE-2021-4238
CVSS v3
9.1
CRITICAL
EPSS Score
1.3 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
Randomly-generated alphanumeric strings contain significantly less entropy than expected. The RandomAlphaNumeric and CryptoRandomAlphaNumeric functions always return strings containing at least one digit from 0 to 9. This significantly reduces the amount of entropy in short strings generated by these functions.
Technical details
- Published
- 2022-12-27
Frequently asked questions
What is CVE-2021-4238?
Randomly-generated alphanumeric strings contain significantly less entropy than expected. The RandomAlphaNumeric and CryptoRandomAlphaNumeric functions always return strings containing at least one digit from 0 to 9. This significantly reduces the amount of entropy in short strings generated by these functions.
Is CVE-2021-4238 actively exploited?
Active exploitation of CVE-2021-4238 has not been confirmed. Its EPSS score was 1.3% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-4238?
CVE-2021-4238 has a CVSS v3 base score of 9.1 (CRITICAL severity).
Is CVE-2021-4238 affecting your environment?
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