# CVE-2019-5010: Null dereference in Python

> A crafted X509 certificate triggers a NULL pointer dereference in Python's parser, causing a denial of service during TLS connections.

- **Severity:** Medium 5.9 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Oct 2019
- **Updated:** 7 Oct 2026
- **Also known as:** ALPINE-CVE-2019-5010, CLEANSTART-2026-AX63397, DEBIAN-CVE-2019-5010, GHSA-jj99-2g8j-7j25, MGASA-2019-0084, PSF-2019-8, SUSE-SU-2019:0271-1, UBUNTU-CVE-2019-5010, openSUSE-SU-2019:0184-1

## What is CVE-2019-5010?

CVE-2019-5010 is a medium-severity vulnerability in Debian Debian Linux, published on 31 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2019-5010?

It affects 7 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `python` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 2.7.14-7.6.1 |
| `python-base` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 2.7.14-7.6.1 |
| `python` | SUSE:Linux Enterprise Module for Desktop Applications 15 | All versions | 2.7.14-7.6.1 |
| `python` | openSUSE:Leap 15.0 | All versions | 2.7.14-lp150.6.6.1 |
| `python-base` | openSUSE:Leap 15.0 | All versions | 2.7.14-lp150.6.6.1 |

Products: Debian Debian Linux, Opensuse Leap, Python Python, Redhat Enterprise Linux, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus.

## How do I fix CVE-2019-5010?

Upgrade to a fixed version.

## Is CVE-2019-5010 being exploited?

There is no known exploitation of CVE-2019-5010 in the wild and no public exploit code.

Public exploit code:

- CVE-2019-5010 Exploit PoC - Python Denial of Service via Malformed X.509v3 Extension (github_poc): https://github.com/JonathanWilbur/CVE-2019-5010

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-5010 and fix it if it is affected.

What it is: CVE-2019-5010 is a medium-severity vulnerability in Debian Debian Linux, published on 31 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-5010 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-5010/ (Markdown: https://insights.sbomify.com/CVE-2019-5010/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-5010
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-5010
- OSV: https://osv.dev/vulnerability/CVE-2019-5010

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-5010/
Summaries are generated and may contain mistakes; the official description above is the record.