CVE-2020-15703 aptdaemon allows unprivileged users to test for the presence of local files via the transaction Locale property
Unprivileged users can determine the existence of arbitrary files on the system by exploiting a lack of input validation in aptdaemon's Locale property.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-15703?
CVE-2020-15703 is a medium-severity path traversal vulnerability in Canonical aptdaemon, published on 31 Oct 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-22
Which versions are affected by CVE-2020-15703?
3 open source packages ship an affected version, including aptdaemon. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
aptdaemon PyPI | All versions | 1.1.1 |
aptdaemon PyPI | All versions | 1.1.1 |
aptdaemon PyPI | All versions | 1.1.1 |
Products include Aptdaemon Project Aptdaemon.
How do I fix CVE-2020-15703?
Upgrade aptdaemon to 1.1.1 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2020-15703 being exploited?
There is no known exploitation of CVE-2020-15703 in the wild and no public exploit code.
Sources
Also known as GHSA-wpmr-q825-x4c6, PYSEC-2026-783, UBUNTU-CVE-2020-15703, USN-4537-1.