{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-58127: PACSgear MediaWriter 5.2.1 Unauthenticated RCE via .NET Remoting TCP Service","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-58127","status":"final","version":"1","initial_release_date":"2026-07-01T14:41:04.970Z","current_release_date":"2026-07-01T17:25:29.591Z","revision_history":[{"date":"2026-07-01T14:41:04.970Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"PACSgear MediaWriter 5.2.1 exposes a .NET Remoting TCP service on port 9000 via PacsgearMediaServerEngine.dll, registered with ObjectURIs RemoteObj and UIRemoteObj, without any authentication requirement. By exploiting the MarshalByRefObject object unmarshalling technique and implementing .NET WebClient class methods, an unauthenticated remote attacker can read and write arbitrary files on the host filesystem. The ObjectURIs are identical across all installations by default. Chaining the arbitrary file write primitive with DLL hijacking opportunities in the MediaWriter service (which runs as NT Authority\\\\SYSTEM and loads missing DLLs such as CRYPTBASE.DLL from the application directory) enables unauthenticated remote code execution as SYSTEM upon service restart.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-58127 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-58127"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-58127"},{"category":"external","summary":"Researcher Disclosure","url":"https://gist.github.com/VAMorales/dc679ecab30b7045fa07bf3249a034d8"},{"category":"external","summary":"Product Webpage","url":"https://www.hyland.com/en/solutions/products/pacsgear"},{"category":"external","summary":"vulncheck.com","url":"https://www.vulncheck.com/advisories/pacsgear-mediawriter-unauthenticated-rce-via-net-remoting-tcp-service"}]},"product_tree":{"branches":[{"category":"vendor","name":"Hyland","branches":[{"category":"product_name","name":"PACSgear MediaWriter","branches":[{"category":"product_version","name":"5.2.1","product":{"name":"Hyland PACSgear MediaWriter 5.2.1","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:hyland:pacsgear_mediawriter:5.2.1:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-58127","title":"PACSgear MediaWriter 5.2.1 Unauthenticated RCE via .NET Remoting TCP Service","notes":[{"category":"description","text":"PACSgear MediaWriter 5.2.1 exposes a .NET Remoting TCP service on port 9000 via PacsgearMediaServerEngine.dll, registered with ObjectURIs RemoteObj and UIRemoteObj, without any authentication requirement. By exploiting the MarshalByRefObject object unmarshalling technique and implementing .NET WebClient class methods, an unauthenticated remote attacker can read and write arbitrary files on the host filesystem. The ObjectURIs are identical across all installations by default. Chaining the arbitrary file write primitive with DLL hijacking opportunities in the MediaWriter service (which runs as NT Authority\\\\SYSTEM and loads missing DLLs such as CRYPTBASE.DLL from the application directory) enables unauthenticated remote code execution as SYSTEM upon service restart.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","baseScore":9.3,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}