CVE-2026-11386An input validation and injection vulnerability exists in Canonical ubuntu-pro-client (formerly ubuntu-advantage-tools).
Updated under an hour ago ()
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An input validation and injection vulnerability exists in Canonical ubuntu-pro-client (formerly ubuntu-advantage-tools). The client constructs APT source files (such as /etc/apt/sources.list.d/ubuntu-.list or their DEB822 equivalents) using data received directly from the contract server response via the directives.suites[] and directives.aptURL fields. Because the client utilizes Python's str.format() to write these files without performing escaping, validation, or newline character filtering, a malicious or tampered contract response containing embedded newline (\n) characters can successfully inject arbitrary, attacker-controlled deb configuration lines into root-owned APT sources. When combined with the unvalidated additionalPackages[] field—which is passed positionally into a root-executed apt-get install command—an attacker capable of spoofing or manipulating the contract response (e.g., via a compromised internal infrastructure, an intercepted connection utilizing a trusted CA, or local logical bugs) can force the client to fetch and install malicious packages. This ultimately leads to arbitrary code execution with root privileges on the affected system. This component is preinstalled on supported Ubuntu Server releases and auto-attaches by default on cloud provider Ubuntu Pro images.
- CVSS
- 9.0 CRITICAL (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-20
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Awaiting Analysis
- Record last updated
- Jul 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
No affected products are listed yet.
References
- https://ubuntu.com/security/CVE-2026-11386
The CVE record on cve.org NVD's entry
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