CVE-2026-12391
ubuntu-pro-client Local Privilege Escalation and Information Disclosure via Symlink Arbitrary File Read in collect-logs
Description
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.
INFO
Published Date :
July 16, 2026, 1:16 p.m.
Last Modified :
July 16, 2026, 1:51 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-12391
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | cc1ad9ee-3454-478d-9317-d3e869d708bc | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update ubuntu-pro-client to the latest version.
- Verify log collection processes do not follow symlinks.
- Ensure log directories have proper ownership and permissions.
- Restrict unprivileged user access to sensitive system files.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-12391.
| URL | Resource |
|---|---|
| https://ubuntu.com/security/CVE-2026-12391 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12391 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-12391
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12391 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12391 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 16, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/canonical/ubuntu-pro-client', 'vendor': 'Canonical', 'product': 'ubuntu-pro-client (ubuntu-advantage-tools)', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '37.3', 'versionType': 'python'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-pro-client', 'collectionURL': 'https://github.com/canonical/', 'defaultStatus': 'unaffected'}, {'repo': 'https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools', 'vendor': 'Canonical', 'product': 'Ubuntu 26.04 LTS', 'versions': [{'status': 'unaffected', 'version': '37.2ubuntu0.1', 'versionType': 'dpkg'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-advantage-tools', 'collectionURL': 'https://launchpad.net/ubuntu/resolute', 'defaultStatus': 'affected'}, {'repo': 'https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools', 'vendor': 'Canonical', 'product': 'Ubuntu 24.04 LTS', 'versions': [{'status': 'unaffected', 'version': '37.2ubuntu~24.04.1', 'versionType': 'dpkg'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-advantage-tools', 'collectionURL': 'https://launchpad.net/ubuntu/noble', 'defaultStatus': 'affected'}, {'repo': 'https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools', 'vendor': 'Canonical', 'product': 'Ubuntu 22.04 LTS', 'versions': [{'status': 'unaffected', 'version': '37.2ubuntu~22.04.1', 'versionType': 'dpkg'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-advantage-tools', 'collectionURL': 'https://launchpad.net/ubuntu/jammy', 'defaultStatus': 'affected'}, {'repo': 'https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools', 'vendor': 'Canonical', 'product': 'Ubuntu 20.04 LTS', 'versions': [{'status': 'unaffected', 'version': '37.1ubuntu0~20.04.1', 'versionType': 'dpkg'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-advantage-tools', 'collectionURL': 'https://launchpad.net/ubuntu/focal', 'defaultStatus': 'affected'}, {'repo': 'https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools', 'vendor': 'Canonical', 'product': 'Ubuntu 18.04 LTS', 'versions': [{'status': 'unaffected', 'version': '37.1ubuntu0~18.04.1', 'versionType': 'dpkg'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-advantage-tools', 'collectionURL': 'https://launchpad.net/ubuntu/bionic', 'defaultStatus': 'affected'}, {'repo': 'https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools', 'vendor': 'Canonical', 'product': 'Ubuntu 16.04 LTS', 'versions': [{'status': 'unaffected', 'version': '37.1ubuntu0~16.04.1', 'versionType': 'dpkg'}], 'platforms': ['Linux'], 'packageName': 'ubuntu-advantage-tools', 'collectionURL': 'https://launchpad.net/ubuntu/xenial', 'defaultStatus': 'affected'}] Added Description 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. Added CVSS V3.1 AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N Added CWE CWE-59 Added Reference https://ubuntu.com/security/CVE-2026-12391