Answer in brief
CVE-2026-12249 records a Critical severity (CVSS 9.0) vulnerability in Canonical ADSys Trust Store Poisoning via Plaintext HTTP Certificate Auto-Enrollment. The current sources do not mark it as known exploited. The current feed maps github.com/ubuntu/adsys (go), github.com/ubuntu/adsys (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps github.com/ubuntu/adsys (go), github.com/ubuntu/adsys (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| github.com/ubuntu/adsysgo | <0.16.3-0.20250318112551-8b1939f96d38 | 0.16.3-0.20250318112551-8b1939f96d38 |
| github.com/ubuntu/adsysgo | >=0 | Not reported |
Published upstream
Jun 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 22, 2026
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.
Quoted source text, attributed separately from HOL analysis.