{"id":"CVE-2026-11386","state":"PUBLISHED","title":"ubuntu-pro-client Input Validation Vulnerability Leading to Arbitrary APT Directive Injection and Remote Code Execution","description":"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.","publishedAt":"2026-07-16T12:16:02.508Z","updatedAt":"2026-07-16T13:31:16.910Z","severity":{"score":9,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","source":"canonical"},"assigner":"canonical","products":["Canonical ubuntu-pro-client (ubuntu-advantage-tools)","Canonical Ubuntu 26.04 LTS","Canonical Ubuntu 24.04 LTS","Canonical Ubuntu 22.04 LTS","Canonical Ubuntu 20.04 LTS","Canonical Ubuntu 18.04 LTS","Canonical Ubuntu 16.04 LTS","Canonical Ubuntu 14.04 LTS"],"affected":[{"vendor":"Canonical","product":"ubuntu-pro-client (ubuntu-advantage-tools)","packageName":"ubuntu-pro-client","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"37.3","versionType":"python"}],"platforms":["Linux"],"collectionURL":"https://github.com/canonical/","repo":"https://github.com/canonical/ubuntu-pro-client"},{"vendor":"Canonical","product":"Ubuntu 26.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.2ubuntu0.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/resolute","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 24.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.2ubuntu~24.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/noble","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 22.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.2ubuntu~22.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/jammy","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 20.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.1ubuntu0~20.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/focal","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 18.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.1ubuntu0~18.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/bionic","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 16.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.1ubuntu0~16.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/xenial","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 14.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"19.7ubuntu0.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/trusty","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"}],"references":["https://ubuntu.com/security/CVE-2026-11386"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T20:10:52.580Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/11xxx/CVE-2026-11386.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-11386","state":"PUBLISHED","datePublished":"2026-07-16T12:16:02.508Z","dateUpdated":"2026-07-16T13:31:16.910Z","assignerShortName":"canonical","assignerOrgId":"cc1ad9ee-3454-478d-9317-d3e869d708bc","dateReserved":"2026-06-05T15:11:57.169Z"},"containers":{"cna":{"title":"ubuntu-pro-client Input Validation Vulnerability Leading to Arbitrary APT Directive Injection and Remote Code Execution","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Canonical","product":"ubuntu-pro-client (ubuntu-advantage-tools)","packageName":"ubuntu-pro-client","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"37.3","versionType":"python"}],"platforms":["Linux"],"collectionURL":"https://github.com/canonical/","repo":"https://github.com/canonical/ubuntu-pro-client"},{"vendor":"Canonical","product":"Ubuntu 26.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.2ubuntu0.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/resolute","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 24.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.2ubuntu~24.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/noble","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 22.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.2ubuntu~22.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/jammy","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 20.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.1ubuntu0~20.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/focal","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 18.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.1ubuntu0~18.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/bionic","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 16.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"37.1ubuntu0~16.04.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/xenial","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"},{"vendor":"Canonical","product":"Ubuntu 14.04 LTS","packageName":"ubuntu-advantage-tools","defaultStatus":"affected","versions":[{"version":"19.7ubuntu0.1","status":"unaffected","versionType":"dpkg"}],"platforms":["Linux"],"collectionURL":"https://launchpad.net/ubuntu/trusty","repo":"https://launchpad.net/ubuntu/+source/ubuntu-advantage-tools"}],"references":[{"url":"https://ubuntu.com/security/CVE-2026-11386","tags":["vdb-entry"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseSeverity":"CRITICAL","baseScore":9,"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","description":"CWE-20 Improper input validation","type":"CWE"}]}],"providerMetadata":{"shortName":"canonical","orgId":"cc1ad9ee-3454-478d-9317-d3e869d708bc","dateUpdated":"2026-07-16T12:16:02.508Z"},"datePublic":"2026-07-16T12:00:00.000Z","impacts":[{"capecId":"CAPEC-242","descriptions":[{"lang":"en","value":"CAPEC-242 Code Injection"}]}],"credits":[{"lang":"en","value":"Frederick Jerusha","type":"finder"}],"source":{"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-16T13:30:45.443694Z","id":"CVE-2026-11386","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-16T13:31:16.910Z"}}]}}}