CVE-2026-12391 PUBLISHED

ubuntu-pro-client Local Privilege Escalation and Information Disclosure via Symlink Arbitrary File Read in collect-logs

Assigner: canonical
Reserved: 16.06.2026 Published: 16.07.2026 Updated: 16.07.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
CVSS Score: 5

Product Status

Vendor Canonical
Product ubuntu-pro-client (ubuntu-advantage-tools)
Versions Default: unaffected
  • affected from 0 to 37.3 (excl.)
Vendor Canonical
Product Ubuntu 26.04 LTS
Versions Default: affected
  • Version 37.2ubuntu0.1 is unaffected
Vendor Canonical
Product Ubuntu 24.04 LTS
Versions Default: affected
  • Version 37.2ubuntu~24.04.1 is unaffected
Vendor Canonical
Product Ubuntu 22.04 LTS
Versions Default: affected
  • Version 37.2ubuntu~22.04.1 is unaffected
Vendor Canonical
Product Ubuntu 20.04 LTS
Versions Default: affected
  • Version 37.1ubuntu0~20.04.1 is unaffected
Vendor Canonical
Product Ubuntu 18.04 LTS
Versions Default: affected
  • Version 37.1ubuntu0~18.04.1 is unaffected
Vendor Canonical
Product Ubuntu 16.04 LTS
Versions Default: affected
  • Version 37.1ubuntu0~16.04.1 is unaffected

Credits

  • Mateusz Gierblinski finder

References

Problem Types

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

Impacts

  • CAPEC-132 Symlink Attack