What is CVE-2026-4428?

CVE-2026-4428 is a high-severity vulnerability in AWS Aws-Lc, classified under Improper Check for Certificate Revocation. CVSS score: 7.4/10. Published 2026-03-19.

How severe is CVE-2026-4428?

High severity. CVSS v3 base score is 7.4 out of 10.

Vulnerability in AWS Aws-Lc

CVE-2026-4428

A logic error in CRL distribution point validation in AWS-LC before 1.71.0 causes partitioned CRLs to be incorrectly rejected as out of scope, which allows a revoked certificate to bypass certificate revocation checks. To remediate this issue, users should upgrade to AWS-LC 1.71.0 or AWS-LC-FIPS-3.3.0.

EPSS: 0.003 (16.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Aws Aws-lc — versions 1.24.0
Aws Aws-lc-fips — versions 3.0.0

Weakness classification (CWE)

CWE-299 — Improper Check for Certificate Revocation

References

ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory)
ff89ba41-3aa1-4d27-914a-91399e9639e5 (patch)

Frequently asked questions

What is CVE-2026-4428?: CVE-2026-4428 is a high-severity vulnerability in AWS Aws-Lc, classified under Improper Check for Certificate Revocation. CVSS score: 7.4/10. Published 2026-03-19.
How severe is CVE-2026-4428?: High severity. CVSS v3 base score is 7.4 out of 10.