Ubuntu Pro Client: Insecure Symlink Follow leads to Info Disclosure
CVE-2026-12391 Published on July 16, 2026

ubuntu-pro-client Local Privilege Escalation and Information Disclosure via Symlink Arbitrary File Read in collect-logs
An insecure symlink following vulnerability exists in Canonical ubuntu-pro-client (formerly ubuntu-advantage-tools) within the pro collect-logs command framework. The utility creates or utilizes predictable temporary file paths or user-accessible log directories when gathering diagnostic information without verifying the file type or ownership. An unprivileged local attacker can exploit this behavior by creating a symbolic link (symlink) at a predictable destination path pointing to an arbitrary, root-readable file (such as /etc/shadow or private files within /root). When a root administrator or operator subsequently executes the pro collect-logs command, the tool follows the user-controlled symlink, reads the target file, and compresses its contents into the resulting diagnostic support archive. Because the output archive remains readable by the unprivileged user, the attacker can extract and read the sensitive root-owned files, leading to a complete information disclosure of system secrets.

NVD

Vulnerability Analysis

CVE-2026-12391 can be exploited with local system access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
NONE
Availability Impact:
NONE

Weakness Type

What is an insecure temporary file Vulnerability?

The software attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

CVE-2026-12391 has been classified to as an insecure temporary file vulnerability or weakness.


Affected Versions

Canonical ubuntu-pro-client (ubuntu-advantage-tools): Canonical Ubuntu 26.04 LTS: Canonical Ubuntu 24.04 LTS: Canonical Ubuntu 22.04 LTS: Canonical Ubuntu 20.04 LTS: Canonical Ubuntu 18.04 LTS: Canonical Ubuntu 16.04 LTS: