python-cryptography verifier accepts wildcard DNS names allowing escape from permittedSubtrees
At a glance
Severity
MEDIUM 6.9
EPSS
EPSS 0.24 % · percentile 15 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
GitHub_M
NVD status
Awaiting Analysis
Description
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In versions 45.0.0 through 48.0.0, if an intermediate constrained CA permits the DNS name foo.example.com, and the leaf certificate has a wildcard in its DNS SAN of *.example.com, python-cryptography's verifier accepts which allows escaping outside of the permitted names. The core issue is in DNSConstraint::matches, where a wildcard pattern was treated as matching a more-specific permitted constraint even though *.example.com can expand to sibling names such as bar.example.com outside foo.example.com. This allows acceptance of an invalid certificate chain. This issue is fixed in 49.0.0.
