Vulnerability in Canonical ubuntu-pro-client (CVE-2026-12391)
Summary
Vulnerability in Canonical ubuntu-pro-client (CVE-2026-12391). Confidential information can be exposed externally.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-12391 has been found in Canonical ubuntu-pro-client.
Confidential information can be exposed externally. CVSS score: 5.0/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Canonical ubuntu-pro-client CVE-2026-12391" on the vendor's site.
CVE-2026-12391 (Canonical ubuntu-pro-client) — CWE-59 / CVSS v3 5.0
Attack vector: local
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-59) exists in Canonical ubuntu-pro-client.
Check the vendor advisory for the affected versions of Canonical ubuntu-pro-client.
Severity: Medium (CVSS 5.0/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Canonical ubuntu-pro-client を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-12391 ubuntu-advantage-tools Fixed in: 37.2ubuntu~22.04.1
References
- web nvd.nist.gov
- web security@ubuntu.com
- web github.com