# CVE-2020-5202: Information disclosure in n/a

> Local attackers can hijack a hardcoded TCP port to intercept sensitive data from apt-cacher-ng administrative requests, exposing credentials or configuration details.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jan 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-5202, GHSA-ppjv-mwcc-539j, UBUNTU-CVE-2020-5202

## What is CVE-2020-5202?

CVE-2020-5202 is a medium-severity vulnerability in Debian Debian Linux, published on 21 Jan 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port. The /usr/lib/apt-cacher-ng/acngtool program attempts to connect to apt-cacher-ng via TCP on localhost port 3142, even if the explicit SocketPath=/var/run/apt-cacher-ng/socket command-line option is passed. The cron job /etc/cron.daily/apt-cacher-ng (which is active by default) attempts this periodically. Because 3142 is an unprivileged port, any local user can try to bind to this port and will receive requests from acngtool. There can be sensitive data in these requests, e.g., if AdminAuth is enabled in /etc/apt-cacher-ng/security.conf. This sensitive data can leak to unprivileged local users that manage to bind to this port before the apt-cacher-ng daemon can.

## Which versions are affected by CVE-2020-5202?

It affects 4 products.


Products: Apt-Cacher-Ng Project Apt-Cacher-Ng, Debian Debian Linux, Opensuse Backports, Opensuse Leap.

## How do I fix CVE-2020-5202?

Apply the vendor's patch.

## Is CVE-2020-5202 being exploited?

There is no known exploitation of CVE-2020-5202 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2019-18899](https://insights.sbomify.com/CVE-2019-18899/): apt-cacher-ng insecure use of /run/apt-cacher-ng (medium 6.2)
- [CVE-2017-7443](https://insights.sbomify.com/CVE-2017-7443/): Other in n/a (medium 6.1)
- [CVE-2025-11146](https://insights.sbomify.com/CVE-2025-11146/): Reflected Cross-site scripting (XSS) vulnerability in Apt-Cacher-NG (medium 5.1)
- [CVE-2025-11147](https://insights.sbomify.com/CVE-2025-11147/): Reflected Cross-site scripting (XSS) vulnerability in Apt-Cacher-NG (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5202 and fix it if it is affected.

What it is: CVE-2020-5202 is a medium-severity vulnerability in Debian Debian Linux, published on 21 Jan 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-5202 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-2020-5202/ (Markdown: https://insights.sbomify.com/CVE-2020-5202/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5202
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5202
- OSV: https://osv.dev/vulnerability/CVE-2020-5202

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5202/
Summaries are generated and may contain mistakes; the official description above is the record.