CVE-2026-34073
cryptography has incomplete DNS name constraint enforcement on peer names
Description
cryptography 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.
INFO
Published Date :
March 31, 2026, 3:15 a.m.
Last Modified :
April 6, 2026, 3:30 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Update the cryptography package.
- Ensure the package version is 46.0.6 or higher.
- Re-validate DNS name constraints and peer name validation.
Public PoC/Exploit Available at Github
CVE-2026-34073 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-34073.
| URL | Resource |
|---|---|
| https://github.com/pyca/cryptography/security/advisories/GHSA-m959-cc7f-wv43 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-34073 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-34073
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
MCP Memory Service for Claude Brain Proxy
Dockerfile Python HTML Shell JavaScript PowerShell Batchfile CSS Slim TypeScript
Akamai Cloud migration evaluation - AWS Bookstore Demo
Makefile Dockerfile HTML Go Template Shell JavaScript Python HCL
None
Open-source persistent memory for AI agent pipelines (LangGraph, CrewAI, AutoGen) and Claude. REST API + knowledge graph + autonomous consolidation.
mcp memory semantic-search vector-database claude vector-storage sqlite-vec mcp-server model-context-protocol agent-memory agentic-ai ai-agents autogen crewai knowledge-graph langgraph long-term-memory multi-agent open-source rag
Python Dockerfile Shell HTML Slim JavaScript Batchfile PowerShell CSS TypeScript
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-34073 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-34073 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 06, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:cryptography.io:cryptography:*:*:*:*:*:python:*:* versions up to (excluding) 46.0.6 Added Reference Type GitHub, Inc.: https://github.com/pyca/cryptography/security/advisories/GHSA-m959-cc7f-wv43 Types: Vendor Advisory -
New CVE Received by [email protected]
Mar. 31, 2026
Action Type Old Value New Value Added Description cryptography 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. Added CVSS V4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-295 Added Reference https://github.com/pyca/cryptography/security/advisories/GHSA-m959-cc7f-wv43