AWS-LC <1.71.0: CRL D. Point Validation Logic Error Bypasses Revoked Cert
CVE-2026-4428 Published on March 19, 2026
CRL Distribution Point Scope Check Logic Error in AWS-LC
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.
Vulnerability Analysis
CVE-2026-4428 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Improper Check for Certificate Revocation
The software does not check or incorrectly checks the revocation status of a certificate, which may cause it to use a certificate that has been compromised. An improper check for certificate revocation is a far more serious flaw than related certificate failures. This is because the use of any revoked certificate is almost certainly malicious. The most common reason for certificate revocation is compromise of the system in question, with the result that no legitimate servers will be using a revoked certificate, unless they are sorely out of sync.
Products Associated with CVE-2026-4428
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Affected Versions
AWS-LC:- Version 1.24.0 and below 1.71.0 is affected.
- Version 3.0.0 and below 3.3.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.