CVE-2026-12391 | 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.

Published: 2026-07-16 Last update: 2026-07-16 Assigner: [email protected] Source: [email protected]
NVD Status：Undergoing Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-12391 is rated Low Risk (30.8/100): CVSS Medium severity. Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-12391

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

EPSS has not published a score for this CVE yet—common while NVD analysis or FIRST scoring is still pending. Monitor daily updates and reassess once scores appear.

Common vulnerability scoring system (CVSS) metrics for CVE-2026-12391

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.3 3.6 [email protected]

Weakness enumeration for CVE-2026-12391

GitHub Security Advisory for CVE-2026-12391

GHSA-whf7-7mxf-ww93 · Severity: medium — An insecure symlink following vulnerability exists in Canonical ubuntu-pro-client (formerly...

OS Trackers for CVE-2026-12391

vendor priority summary link
ubuntu medium CVE-2026-12391 medium priority: Ubuntu including 1 source packages (ubuntu-advantage-tools), 9 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): released 6, ignored 1, needs-triage 1, not-affected 1. https://ubuntu.com/security/CVE-2026-12391

Affected software / configurations for CVE-2026-12391

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-12391

cvelogic Threat Intelligence