CVE-2025-61727
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk20th percentile - higher than 20% of all known CVEs
Summary
An excluded subdomain constraint in a certificate chain does not restrict the usage of wildcard SANs in the leaf certificate. For example a constraint that excludes the subdomain test.example.com does not prevent a leaf certificate from claiming the SAN *.example.com.
Risk Assessment
An attacker may obtain a certificate with a wildcard SAN that covers excluded subdomains, potentially leading to unauthorized access to services in those subdomains.
Recommendation
Update certificate validation software to properly enforce excluded subdomain constraints in the presence of wildcard SANs. Consider re-evaluating trust in certificates with wildcard SANs.
Other vulnerabilities in Certificate validation
See all- CVE-2026-32281High
Validating certificate chains which use policies is unexpectedly inefficient when certificates in the chain contain a very large number of policy mappings, possibly causing denial of service.
- CVE-2025-58188High
Validating certificate chains which contain DSA public keys can cause programs to panic, due to an interface cast that assumes they implement the Equal method. This affects programs which validate arbitrary certificate chains.
Original NVD description (English source)
An excluded subdomain constraint in a certificate chain does not restrict the usage of wildcard SANs in the leaf certificate. For example a constraint that excludes the subdomain test.example.com does not prevent a leaf certificate from claiming the SAN *.example.com.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS