CVE-2026-12249

June 22, 2026, 8:18 p.m.

9.0
Critical

Description

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.

Product(s) Impacted

Vendor Product Versions
Canonical
  • Ad Sys
  • <0.16.3

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-348
Use of Less Trusted Source
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.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a canonical ad_sys <0.16.3 / / / / / / /

References

https://github.com/ubuntu/adsys/commit/8b1939f96d3827b4426eb06c1ced5bf317b0a99d
https://ubuntu.com/security/CVE-2026-12249

Tags

[email protected]
CWE-348
2026-06-22
CVE-2026-12249

CVSS Score

9.0 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: HIGH
  • Attack Requirements: NONE
  • Privileges Required: NONE
  • User Interaction: NONE
  • Scope:
  • Confidentiality Impact: HIGH
  • Integrity Impact: HIGH
  • Availability Impact: HIGH
  • Exploit Maturity: PROOF_OF_CONCEPT

    • 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:N/AU:Y/R:I/V:D/RE:L/U:Red

    View Vector String

Timeline

Published: June 22, 2026, 6:16 p.m.
Last Modified: June 22, 2026, 8:18 p.m.

Status : Awaiting Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.