Vulnerability · Published Oct 31, 2020 · Assigned by canonical

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

Medium 4.0

In plain English

A medium-severity path traversal in aptdaemon from Canonical. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.0Medium

Exploit odds (30 days)0.5%top 57.7% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	aptdaemon	1.1.1	GHSA-wpmr-q825-x4c6
PyPI	aptdaemon	1.1.1	PYSEC-2026-783

Affected products (as reported)

Vendor	Product	Versions
Canonical	aptdaemon	unspecified – before 1.1.1+bzr982-0ubuntu32.2unspecified – before 1.1.1+bzr982-0ubuntu19.4unspecified – before 1.1.1+bzr982-0ubuntu14.4

Weakness: CWE-22 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

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