{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-11858: Missing authorization in Quanos SCHEMA ST4 Client Update Service allows arbitrary file overwrite as SYSTEM","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-11858","status":"final","version":"1","initial_release_date":"2026-06-17T11:50:47.666Z","current_release_date":"2026-06-17T14:56:22.560Z","revision_history":[{"date":"2026-06-17T11:50:47.666Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"Quanos SCHEMA ST4 on-premises contains a local privilege escalation vulnerability in the Client Update Service. The update service runs as NT AUTHORITY\\SYSTEM and exposes a .NET Remoting interface over a named pipe without sufficient access controls or authorization. A local authenticated low-privileged user can connect to the interface and invoke privileged update methods such as Update(). This allows arbitrary file write and delete operations with SYSTEM privileges and can be used to achieve local privilege escalation.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-11858 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-11858"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-11858"},{"category":"external","summary":"r.sec-consult.com","url":"https://r.sec-consult.com/quanos"}]},"product_tree":{"branches":[{"category":"vendor","name":"Quanos Solutions GmbH","branches":[{"category":"product_name","name":"SCHEMA ST4","branches":[{"category":"product_version","name":"SCHEMA ST4 on-premises, all versions","product":{"name":"Quanos Solutions GmbH SCHEMA ST4 SCHEMA ST4 on-premises, all versions","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:quanos_solutions_gmbh:schema_st4:schema_st4_on-premises\\,_all_versions:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-11858","title":"Missing authorization in Quanos SCHEMA ST4 Client Update Service allows arbitrary file overwrite as SYSTEM","notes":[{"category":"description","text":"Quanos SCHEMA ST4 on-premises contains a local privilege escalation vulnerability in the Client Update Service. The update service runs as NT AUTHORITY\\SYSTEM and exposes a .NET Remoting interface over a named pipe without sufficient access controls or authorization. A local authenticated low-privileged user can connect to the interface and invoke privileged update methods such as Update(). This allows arbitrary file write and delete operations with SYSTEM privileges and can be used to achieve local privilege escalation.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","baseScore":8.4,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}