Medium severity · published Jul 16, 2026
CVE-2026-12391
ubuntu-pro-client Local Privilege Escalation and Information Disclosure via Symlink Arbitrary File Read in collect-logs
5.0
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
U1
Ubuntu 16.04 LTS · Canonical
All versions, or not specified · source: vendor
U1
Ubuntu 18.04 LTS · Canonical
All versions, or not specified · source: vendor
U2
Ubuntu 20.04 LTS · Canonical
All versions, or not specified · source: vendor
U2
Ubuntu 22.04 LTS · Canonical
All versions, or not specified · source: vendor
U2
Ubuntu 24.04 LTS · Canonical
All versions, or not specified · source: vendor
U2
Ubuntu 26.04 LTS · Canonical
All versions, or not specified · source: vendor
UU
ubuntu-pro-client (ubuntu-advantage-tools) · Canonical
before 37.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-12391
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-12391
ubuntu.com
https://ubuntu.com/security/CVE-2026-12391
More from Ubuntu 16.04 LTS
9.0
CVE-2026-11386
ubuntu-pro-client Input Validation Vulnerability Leading to Arbitrary APT Directive Injection and Remote Code Execution
8.4
CVE-2026-15226
snapd snap-confine Sandbox Confinement Bypass via Omission of setuid Restriction in Seccomp Templates
5.6
CVE-2024-5300
AppArmor Base Profile Misconfiguration in snapd Permits Confined Snaps Unauthorized Access to Hashed Passwords via systemd-userdbd
5.5
CVE-2026-9494
ubuntu-pro-client Information Disclosure via Cleartext Bearer Token Exposure in Process Command Line
