# CVE-2019-15795: python-apt uses MD5 for validation

> Man-in-the-middle attackers can install altered packages by exploiting weak MD5 validation in python-apt, requiring users to upgrade the library.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 26 Mar 2020
- **Updated:** 16 Sep 2024
- **Also known as:** DEBIAN-CVE-2019-15795, GHSA-rp8m-h266-53jh, UBUNTU-CVE-2019-15795

## What is CVE-2019-15795?

CVE-2019-15795 is a medium-severity vulnerability in Canonical Python-apt, published on 26 Mar 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

python-apt only checks the MD5 sums of downloaded files in `Version.fetch_binary()` and `Version.fetch_source()` of apt/package.py in version 1.9.0ubuntu1 and earlier. This allows a man-in-the-middle attack which could potentially be used to install altered packages and has been fixed in versions 1.9.0ubuntu1.2, 1.6.5ubuntu0.1, 1.1.0~beta1ubuntu0.16.04.7, 0.9.3.5ubuntu3+esm2, and 0.8.3ubuntu7.5.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2019-15795?

10 open source packages ship an affected version, including python-apt. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `python-apt` | PyPI | All versions | 0.8.3ubuntu7.5 |
| `python-apt` | PyPI | All versions | 0.8.3ubuntu7.5 |
| `python-apt` | PyPI | From 0.9.0 | 0.9.3.5ubuntu3 |
| `python-apt` | PyPI | From 0.9.0 | 0.9.3.5ubuntu3 |
| `python-apt` | PyPI | From 1.0.0 | 1.1.0 |
| `python-apt` | PyPI | From 1.0.0 | 1.1.0 |
| `python-apt` | PyPI | From 1.2.0 | 1.6.5ubuntu0.1 |
| `python-apt` | PyPI | From 1.2.0 | 1.6.5ubuntu0.1 |
| `python-apt` | PyPI | From 1.7.0 | 1.9.0ubuntu1.2 |
| `python-apt` | PyPI | From 1.7.0 | 1.9.0ubuntu1.2 |

Products: Debian Python-Apt, Ubuntu Python-Apt.

## How do I fix CVE-2019-15795?

Upgrade python-apt to a fixed version for your release line: 0.8.3ubuntu7.5, 0.9.3.5ubuntu3, 1.1.0 or 1.6.5ubuntu0.1.

## Is CVE-2019-15795 being exploited?

There is no known exploitation of CVE-2019-15795 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Python-apt

- [CVE-2019-15796](https://insights.sbomify.com/CVE-2019-15796/): python-apt downloads from untrusted sources (medium 4.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-15795 and fix it if it is affected.

What it is: CVE-2019-15795 is a medium-severity vulnerability in Canonical Python-apt, published on 26 Mar 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2019-15795 in the wild and no public exploit code.

Affected packages and fixed versions:
- python-apt (PyPI): affected all versions; fixed in 0.8.3ubuntu7.5
- python-apt (PyPI): affected all versions; fixed in 0.8.3ubuntu7.5
- python-apt (PyPI): affected from 0.9.0; fixed in 0.9.3.5ubuntu3
- python-apt (PyPI): affected from 0.9.0; fixed in 0.9.3.5ubuntu3
- python-apt (PyPI): affected from 1.0.0; fixed in 1.1.0
- python-apt (PyPI): affected from 1.0.0; fixed in 1.1.0
- python-apt (PyPI): affected from 1.2.0; fixed in 1.6.5ubuntu0.1
- python-apt (PyPI): affected from 1.2.0; fixed in 1.6.5ubuntu0.1
- python-apt (PyPI): affected from 1.7.0; fixed in 1.9.0ubuntu1.2
- python-apt (PyPI): affected from 1.7.0; fixed in 1.9.0ubuntu1.2

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-2019-15795/ (Markdown: https://insights.sbomify.com/CVE-2019-15795/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-15795
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-15795
- OSV: https://osv.dev/vulnerability/CVE-2019-15795

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-15795/
Summaries are generated and may contain mistakes; the official description above is the record.