# CVE-2026-12391: Canonical ubuntu-pro-client insecure symlink following in collect-logs

Source: https://junglewise.ai/threats/cve-2026-12391-canonical-ubuntu-pro-client-insecure-symlink-following-in-collect  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-16. Updated: 2026-07-16  
License: CC BY 4.0 with a link back

CVE-2026-12391 · Severity: medium · CVSS 5 · Published 2026-07-16

A security vulnerability exists in the Ubuntu Pro client, a tool used to manage enterprise services and diagnostic logs on Ubuntu systems. An attacker with limited access to a computer can trick the system into including sensitive files, such as password hashes or private keys, in a diagnostic report. If an administrator runs the log collection tool, the attacker can then access these secret files from the resulting report, potentially leading to full system compromise.

Technologies: [Canonical Ubuntu 22.04 LTS](https://junglewise.ai/threats/technologies/ubuntu), [Canonical Ubuntu-Pro-Client](https://junglewise.ai/threats/technologies/ubuntu-pro-client). Vendors: [Canonical](https://junglewise.ai/threats/vendors/canonical).

## Quick answers

**Is CVE-2026-12391 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-12391 being exploited in the wild.

**How severe is CVE-2026-12391?** Medium severity, with a CVSS score of 5, published 16 July 2026.

**Which products and versions are affected?** Canonical Ubuntu 22.04 LTS < 37.2ubuntu~22.04.1; Canonical Ubuntu 24.04 LTS < 37.2ubuntu~24.04.1; Canonical Ubuntu 26.04 LTS < 37.2ubuntu0.1; Canonical Ubuntu-Pro-Client < 37.3.

**Is there a fix for CVE-2026-12391?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-12391 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-12391?** Check whether you run Canonical Ubuntu 22.04 LTS, Canonical Ubuntu 24.04 LTS, Canonical Ubuntu 26.04 LTS or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An insecure symlink following vulnerability (CWE-59) exists in the 'pro collect-logs' command of the Canonical ubuntu-pro-client (formerly ubuntu-advantage-tools). The utility uses predictable temporary file paths or user-accessible directories without verifying file ownership or type. A local unprivileged attacker can create a symbolic link at a predictable path pointing to sensitive root-only files (e.g., /etc/shadow). When a root administrator executes the log collection command, the tool follows the symlink, includes the sensitive file in the diagnostic archive, and leaves the archive readable by the unprivileged user. This results in information disclosure of system secrets. The issue is addressed in version 37.3 of the client and corresponding package updates for Ubuntu LTS releases.

## Affected products

- Canonical ubuntu-pro-client (ubuntu-advantage-tools) < 37.3
- Canonical Ubuntu 26.04 LTS < 37.2ubuntu0.1
- Canonical Ubuntu 24.04 LTS < 37.2ubuntu~24.04.1
- Canonical Ubuntu 22.04 LTS < 37.2ubuntu~22.04.1

## Timeline

- 2026-07-16: disclosed
- 2026-07-16: advisory

## References

- [https://github.com/canonical/](https://github.com/canonical/)
- [https://launchpad.net/ubuntu/resolute](https://launchpad.net/ubuntu/resolute)
- [https://launchpad.net/ubuntu/noble](https://launchpad.net/ubuntu/noble)
- [https://launchpad.net/ubuntu/jammy](https://launchpad.net/ubuntu/jammy)
- [https://launchpad.net/ubuntu/focal](https://launchpad.net/ubuntu/focal)
- [https://launchpad.net/ubuntu/bionic](https://launchpad.net/ubuntu/bionic)
- [https://launchpad.net/ubuntu/xenial](https://launchpad.net/ubuntu/xenial)

## Related threats

- [Canonical snapd privilege escalation in snap-confine](https://junglewise.ai/threats/cve-2026-8933-canonical-snapd-privilege-escalation-in-snap-confine)
- [Canonical ubuntu-pro-client information disclosure via process arguments](https://junglewise.ai/threats/cve-2026-9494-canonical-ubuntu-pro-client-information-disclosure-via-process)
- [Canonical ubuntu-pro-client code execution via APT source injection](https://junglewise.ai/threats/cve-2026-11386-canonical-ubuntu-pro-client-code-execution-via-apt-source)