Ubuntu Security NoticesUSN-8555-2

USN-8555-2: Ubuntu Advantage Tools (pro client) regression

USN-8555-1 fixed vulnerabilities in Ubuntu Advantage Tools. On Ubuntu 14.04 LTS only, it was discovered that some machines were unable to enable esm-infra-legacy due to a preemptive apt-helper check. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Bilal Teke discovered that Ubuntu Advantage Tools exposed the Pro bearer token in command-line arguments when validating APT credentials. A local attacker could possibly use this issue to obtain sensitive information and gain unauthorized access to Ubuntu Pro repositories. (CVE-2026-9494) Frederick Jerusha discovered that Ubuntu Advantage Tools did not properly validate data received from the contract server when writing APT source files. An attacker could possibly use this issue to inject arbitrary APT configuration and execute arbitrary code. (CVE-2026-11386) Mateusz Gierblinski discovered that Ubuntu Advantage Tools did not properly handle symbolic links when collecting diagnostic logs. A local attacker could possibly use this issue to obtain sensitive information from files owned by the administrator. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-12391)

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USN-8555-1 fixed vulnerabilities in Ubuntu Advantage Tools.

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Sep 1, 2026 at 3:32 PM UTC
Published by Ubuntu
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Sep 1, 2026 at 4:30 PM UTC
Added to SecurityAlert
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Sep 3, 2026 at 1:10 PM UTC
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Vulnerabilities

CVEs named in this advisory

CVE-2026-9494View CVSS, KEV, EPSS, and threat context CVE-2026-11386View CVSS, KEV, EPSS, and threat context CVE-2026-12391View CVSS, KEV, EPSS, and threat context

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Vendor: Ubuntu
Advisory ID: USN-8555-2
Last source check: Sep 13, 2026 at 5:10 AM UTC

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