{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-12249: Canonical ADSys Trust Store Poisoning via Plaintext HTTP Certificate Auto-Enrollment","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-12249","status":"final","version":"1","initial_release_date":"2026-06-22T15:43:33.890Z","current_release_date":"2026-06-22T17:30:57.314Z","revision_history":[{"date":"2026-06-22T15:43:33.890Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-12249 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-12249"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-12249"},{"category":"external","summary":"ubuntu.com","url":"https://ubuntu.com/security/CVE-2026-12249"},{"category":"external","summary":"github.com","url":"https://github.com/ubuntu/adsys/commit/8b1939f96d3827b4426eb06c1ced5bf317b0a99d"}]},"product_tree":{"branches":[{"category":"vendor","name":"Unspecified vendor","branches":[{"category":"product_name","name":"Unspecified product","branches":[{"category":"product_version_range","name":">=0.13.0 <0.16.3","product":{"name":"Unspecified product >=0.13.0 <0.16.3","product_id":"CSAFPID-1"}}]}]},{"category":"vendor","name":"Canonical","branches":[{"category":"product_name","name":"Ubuntu 20.04 LTS","branches":[{"category":"product_version","name":"*","product":{"name":"Canonical Ubuntu 20.04 LTS *","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_20.04_lts:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0.9.2~20.04.2ubuntu0.1+esm2","product":{"name":"Canonical Ubuntu 20.04 LTS 0.9.2~20.04.2ubuntu0.1+esm2","product_id":"CSAFPID-3","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_20.04_lts:*:*:*:*:*:*:*:*"}}}]}]},{"category":"vendor","name":"Canonical","branches":[{"category":"product_name","name":"Ubuntu 22.04 LTS","branches":[{"category":"product_version","name":"*","product":{"name":"Canonical Ubuntu 22.04 LTS *","product_id":"CSAFPID-4","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_22.04_lts:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0.16.3~22.04.2ubuntu0.22.04.1","product":{"name":"Canonical Ubuntu 22.04 LTS 0.16.3~22.04.2ubuntu0.22.04.1","product_id":"CSAFPID-5","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_22.04_lts:*:*:*:*:*:*:*:*"}}}]}]},{"category":"vendor","name":"Canonical","branches":[{"category":"product_name","name":"Ubuntu 24.04 LTS","branches":[{"category":"product_version","name":"*","product":{"name":"Canonical Ubuntu 24.04 LTS *","product_id":"CSAFPID-6","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_24.04_lts:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0.16.3~24.04.2ubuntu0.24.04.1","product":{"name":"Canonical Ubuntu 24.04 LTS 0.16.3~24.04.2ubuntu0.24.04.1","product_id":"CSAFPID-7","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_24.04_lts:*:*:*:*:*:*:*:*"}}}]}]},{"category":"vendor","name":"Canonical","branches":[{"category":"product_name","name":"Ubuntu 25.10","branches":[{"category":"product_version","name":"*","product":{"name":"Canonical Ubuntu 25.10 *","product_id":"CSAFPID-8","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_25.10:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0.16.3","product":{"name":"Canonical Ubuntu 25.10 0.16.3","product_id":"CSAFPID-9","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_25.10:*:*:*:*:*:*:*:*"}}}]}]},{"category":"vendor","name":"Canonical","branches":[{"category":"product_name","name":"Ubuntu 26.04 LTS","branches":[{"category":"product_version","name":"*","product":{"name":"Canonical Ubuntu 26.04 LTS *","product_id":"CSAFPID-10","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_26.04_lts:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0.16.4ubuntu1","product":{"name":"Canonical Ubuntu 26.04 LTS 0.16.4ubuntu1","product_id":"CSAFPID-11","product_identification_helper":{"cpe":"cpe:2.3:a:canonical:ubuntu_26.04_lts:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-12249","title":"Canonical ADSys Trust Store Poisoning via Plaintext HTTP Certificate Auto-Enrollment","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1","CSAFPID-2","CSAFPID-4","CSAFPID-6","CSAFPID-8","CSAFPID-10"],"fixed":["CSAFPID-3","CSAFPID-5","CSAFPID-7","CSAFPID-9","CSAFPID-11"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"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","baseScore":9,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1","CSAFPID-2","CSAFPID-4","CSAFPID-6","CSAFPID-8","CSAFPID-10"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 0.9.2~20.04.2ubuntu0.1+esm2, 0.16.3, 0.16.3~22.04.2ubuntu0.22.04.1, 0.16.3~24.04.2ubuntu0.24.04.1, 0.16.4ubuntu1.","product_ids":["CSAFPID-1","CSAFPID-2","CSAFPID-4","CSAFPID-6","CSAFPID-8","CSAFPID-10"],"url":"https://github.com/ubuntu/adsys/commit/8b1939f96d3827b4426eb06c1ced5bf317b0a99d"}]}]}