CVE-2026-12391

Summary

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.

Affected Software

VendorProductVersion RangeStatus
Canonicalubuntu-pro-client (ubuntu-advantage-tools)0 < 37.3affected
CanonicalUbuntu 26.04 LTS37.2ubuntu0.1unaffected
CanonicalUbuntu 24.04 LTS37.2ubuntu~24.04.1unaffected
CanonicalUbuntu 22.04 LTS37.2ubuntu~22.04.1unaffected
CanonicalUbuntu 20.04 LTS37.1ubuntu0~20.04.1unaffected
CanonicalUbuntu 18.04 LTS37.1ubuntu0~18.04.1unaffected
CanonicalUbuntu 16.04 LTS37.1ubuntu0~16.04.1unaffected

Weaknesses

  • CWE-59: CWE-59 Improper link resolution before file access ('link following')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References