What is CVE-2021-45489?

CVE-2021-45489 is a high-severity vulnerability in NetBSD, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 7.5/10. Published 2021-12-25.

How severe is CVE-2021-45489?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in NetBSD

CVE-2021-45489

In NetBSD through 9.2, the IPv6 Flow Label generation algorithm employs a weak cryptographic PRNG.

Published 2021-12-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.010 (60.2th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 60.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

NetBSD

Weakness classification (CWE)

CWE-338 — Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

References

arxiv.org/pdf/2112.09604.pdf (Technical Description, Third Party Advisory)
ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2021-001.txt.asc (Vendor Advisory)

Frequently asked questions

What is CVE-2021-45489?: CVE-2021-45489 is a high-severity vulnerability in NetBSD, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 7.5/10. Published 2021-12-25.
How severe is CVE-2021-45489?: High severity. CVSS v3 base score is 7.5 out of 10.