CryptographyApplication · Cryptography.io
CVE-2026-34073
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedcryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to version 46.0.6, DNS name constraints were only validated against SANs within child certificates, and not the "peer name" presented during each validation. Consequently, cryptography would allow a peer named bar.example.com to validate against a wildcard leaf certificate for *.example.com, even if the leaf's parent certificate (or upwards) contained an excluded subtree constraint for bar.example.com. This issue has been patched in version 46.0.6.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe cryptography library before version 46.0.6 failed to properly validate DNS name constraints against the peer name presented during certificate validation. Specifically, excluded subtree constraints in parent certificates were not checked against the actual peer name (e.g., bar.example.com), only against SANs in child certificates. This allowed bypass of name constraints, permitting a peer to validate with a wildcard certificate (*.example.com) even when an excluded subtree constraint existed for that specific name.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
CryptographyApplication
< 46.0.6CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify cryptography library versionRun 'pip show cryptography' or in Python: import cryptography; print(cryptography.__version__)Affected if The version displayed is less than 46.0.6 (e.g., 46.0.5, 46.0.0, 45.0.0, etc.)
-
Confirm library in useCheck project dependencies via requirements.txt, setup.py, or pyproject.toml for 'cryptography'Affected if The project depends on cryptography and the version is below 46.0.6
-
Check for TLS certificate validation usageSearch codebase for uses of ssl.SSLContext.load_verify_locations, ssl.SSLContext.load_cert_chain with custom trust stores, or cryptography.x509 verification callsAffected if The application performs custom certificate validation using the cryptography library's x509 module with name constraints
You are affected if the installed cryptography library version is below 46.0.6 AND your application performs TLS/SSL certificate validation that relies on name constraint checking.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped46.0.6
Upgrade cryptography to version 46.0.6 or later. After upgrading, verify that certificate validation continues to function correctly for all TLS/SSL connections and that excluded subtree constraints are now properly enforced.
46.0.6
- Upgrade the cryptography package to version 46.0.6 or later using your package manager (e.g., pip install --upgrade cryptography>=46.0.6)
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Cryptography
Scoped from the published advisory
- Consultation4.0 h
- Implementation2.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,928.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34073 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-34073 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data