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

Severity: low (CVSS 3.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-10-31 · updated 2026-06-17
Weakness: CWE-22

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.

Affected products

Canonical aptdaemon: 1.1.1-bzr982-0ubuntu14.4, 1.1.1-bzr982-0ubuntu19.4, 1.1.1-bzr982-0ubuntu32.2

References

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

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