EUVD-2026-44911
GHSA-9836-vm3x-qwmj
Severity by source
AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Network-delivered via the contract channel with no target-side privileges or interaction, but AC:H because the attacker must first control or spoof the contract response; scope changes as tampered data becomes root config, yielding full C/I/A impact.
Primary rating from Vendor (canonical).
CVSS VectorVendor: canonical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
2DescriptionCVE.org
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.
Articles & Coverage 1
AnalysisAI
Root-level remote code execution in Canonical's ubuntu-pro-client (formerly ubuntu-advantage-tools) allows an attacker who can spoof or tamper with the Ubuntu Pro contract server response to inject arbitrary APT source lines and install malicious root-owned packages. The client builds /etc/apt/sources.list.d entries from the server's directives.suites[] and directives.aptURL fields via Python str.format() without escaping or newline filtering, and passes additionalPackages[] positionally into a root-run apt-get install. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to control the content of the Ubuntu Pro contract server response processed by ubuntu-pro-client during attach or refresh - concretely, one of: compromise of the contract/internal infrastructure serving directives, a machine-in-the-middle position using a CA the target host trusts, or a local logical bug that lets attacker data reach the response path. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score is 9.0 (Critical) with vector AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H: network vector, no privileges and no user interaction, but high attack complexity and a changed scope reflecting the crossing from a tampered network response into root-owned system configuration. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who controls a malicious or compromised contract endpoint - or who can machine-in-the-middle the client using a certificate the host already trusts - returns a crafted contract response where directives.suites[] or directives.aptURL contains embedded newline characters plus an attacker package name in additionalPackages[]. When the pro client attaches or refreshes, it writes the injected deb source lines into a root-owned APT sources file and then runs apt-get install for the attacker's package, fetching and installing it as root. … |
| Remediation | Apply the Canonical-provided update to ubuntu-pro-client as soon as it is available - patch status: no exact fix version is present in the provided input, so treat the fixed version per Ubuntu release as authoritative from the advisory at https://ubuntu.com/security/CVE-2026-11386, and run 'apt-get update && apt-get install --only-upgrade ubuntu-advantage-tools ubuntu-pro-client' after confirming the target version there. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Immediately conduct an inventory of all systems running ubuntu-pro-client (installed by default on Ubuntu Server 18.04 LTS and later, with automatic attachment on cloud instances) and segment network access to Ubuntu Pro contract servers through firewall restrictions or network isolation. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Wazuh SIEM platform versions 4.4.0 through 4.9.0 contain an unsafe deserialization vulnerability in the DistributedAPI t
BentoML version 1.4.2 and earlier contains an unauthenticated remote code execution vulnerability through insecure deser
pgAdmin 4 contains critical remote code execution vulnerabilities in the Query Tool download and Cloud Deployment endpoi
The renderLocalView function in render/views.py in graphite-web in Graphite 0.9.5 through 0.9.10 uses the pickle Python
BentoML is a Python library for building online serving systems optimized for AI apps and model inference. Rated critica
OpenSSL before 0.9.8za, 1.0.0 before 1.0.0m, and 1.0.1 before 1.0.1h does not properly restrict processing of ChangeCiph
pyLoad download manager version prior to 0.5.0b3.dev77 exposes the Flask SECRET_KEY through an unauthenticated endpoint.
In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and conse
Unauthenticated remote code execution in Marimo ≤0.20.4 allows attackers to execute arbitrary system commands via the `/
pyLoad is the free and open-source Download Manager written in pure Python. Rated medium severity (CVSS 5.3), this vulne
Langflow (a visual LLM pipeline builder) contains a critical unauthenticated code execution vulnerability (CVE-2026-3301
Cross-user flow execution in Langflow (< 1.9.1) lets any authenticated API-key holder run another user's flow by passing
Same weakness CWE-20 – Improper Input Validation
View allShare
External POC / Exploit Code
Leaving vuln.today