CVE-2026-12249: Github.com/ubuntu/adsys Remote Code Execution Vulnerability
CRITICALCVE-2026-12249 is a CRITICAL (CVSS 9.0) remote code execution vulnerability (CWE-348: Use of Less Trusted Source) affecting Github.com/ubuntu/adsys libraries in the Go ecosystem. The issue involves canonical adsys uses a less trusted source. Remediation is available by upgrading affected packages to version 0.16.3-0.20250318112551-8b1939f96d38.
CVE-2026-12249 at a Glance
Security Impact
CVSS: 9.0
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).
How to Fix CVE-2026-12249
To remediate this vulnerability, upgrade all affected Github.com/ubuntu/adsys dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/ubuntu/adsys to 0.16.3-0.20250318112551-8b1939f96d38Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/ubuntu/adsysHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-12249, inspect your project dependencies for Github.com/ubuntu/adsys:
inspect dependencies for github.com/ubuntu/adsysAnalyze the terminal output to locate any version of Github.com/ubuntu/adsys in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.16.3-0.20250318112551-8b1939f96d38), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-348: Use of Less Trusted Source, where the product has two different sources of the same data or information, but it uses the source that has less support for verification, is less trusted, or is less resistant to attack. In Github.com/ubuntu/adsys, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-12249 Affected Github.com/ubuntu/adsys Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/ubuntu/adsys
|
Go |
< 0.16.3-0.20250318112551-8b1939f96d38
|
0.16.3-0.20250318112551-8b1939f96d38
|
References
Frequently Asked Questions
What is CVE-2026-12249?
Which Github.com/ubuntu/adsys versions are affected?
What version fixes CVE-2026-12249?
Is github.com/ubuntu/adsys affected?
What is the CVSS score of CVE-2026-12249?
What CWE is associated with CVE-2026-12249?
How can I check Go dependencies for CVE-2026-12249?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-crm4-q7v4-c2r2",
"modified" : "2026-09-21T22:27:09Z",
"published" : "2026-06-22T18:34:17Z",
"aliases" : [ "CVE-2026-12249" ],
"summary" : "Canonical ADSys Uses a Less Trusted Source",
"details" : "An issue was discovered in Canonical ADSys upstream versions through v0.16.2. During Active Directory Certificate Services (AD CS) certificate auto-enrollment via the vendored Samba client script (internal/policies/certificate/python/vendor_samba/gp/gp_cert_auto_enroll_ext.py), ADSys utilizes a plaintext HTTP connection (http://) instead of a secure HTTPS connection (https://) to request the CA certificate from the Active Directory Certificate Services server (GetCACert). An unauthenticated network attacker positioned between the managed Ubuntu host and the configured AD CS CA hostname can conduct a Man-in-the-Middle (MITM) attack. By intercepting the plaintext HTTP request, the attacker can supply an arbitrary, attacker-controlled Root CA certificate. Because the system automatically accepts this certificate and registers it into the local system trust store via update-ca-certificates, this results in system-wide trust store poisoning. Consequently, TLS clients utilizing the operating system trust store on the affected machine will accept rogue certificates for arbitrary domains, enabling persistent decryption and interception of subsequent TLS connections. This issue is resolved in version v0.16.3.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"
}, {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/S:N/AU:Y/R:I/V:D/RE:L/U:Red"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/ubuntu/adsys"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.16.3-0.20250318112551-8b1939f96d38"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-12249"
}, {
"type" : "WEB",
"url" : "https://github.com/ubuntu/adsys/commit/8b1939f96d3827b4426eb06c1ced5bf317b0a99d"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/ubuntu/adsys"
}, {
"type" : "WEB",
"url" : "https://github.com/ubuntu/adsys/releases/tag/v0.16.3"
}, {
"type" : "WEB",
"url" : "https://ubuntu.com/security/CVE-2026-12249"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-348" ],
"severity" : "CRITICAL",
"github_reviewed" : true,
"github_reviewed_at" : "2026-09-21T22:27:09Z",
"nvd_published_at" : "2026-06-22T18:16:31Z"
}
}