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python-cryptography verifier accepts wildcard DNS names allowing escape from permittedSubtrees

pyca cryptography · CVE-2026-69248
0 news outlets0 CERTs and agencies0 researchers

Assessment: Track

SSVC decision points: exploitation poc, automatable no, technical impact partial, deployment low.

What is it?

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.

Evidence

No coverage recorded yet.

Exploitation

  • Public proof of concept
  • Exploited in the wild
  • Listed as known exploited
CVSS
6.9
EPSS
0.2%
First seen
1 d ago
Status
corroborated

All pyca vulnerabilities