CVE-2026-69248 python-cryptography verifier accepts wildcard DNS names allowing escape from permittedSubtrees
Attackers can bypass certificate name constraints in python-cryptography by using wildcard DNS names, allowing acceptance of invalid certificate chains.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-69248?
CVE-2026-69248 is a medium-severity vulnerability in pyca cryptography, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-295
Which versions are affected by CVE-2026-69248?
3 open source packages ship an affected version, including cryptography.
| Package | Affected | Fixed in |
|---|---|---|
cryptography PyPI | All versions | 49.0.0 |
cryptography PyPI | From 45.0.0 | 49.0.0 |
cryptography PyPI | From 45.0.0 | 49.0.0 |
Linux distribution packages (1)
matrix-synapse openSUSE:Tumbleweed | All versions | 1.163.0-1.1 |
How do I fix CVE-2026-69248?
Upgrade cryptography to 49.0.0 or later.
Is CVE-2026-69248 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-69248 exists.
Sources
Also known as CLEANSTART-2026-FX71748, CLEANSTART-2026-PD33882, CLSA-2026-1790065768, DEBIAN-CVE-2026-69248, ECHO-1e23-77eb-13c2, GHSA-m2h6-j472-rp4c and 41 more.