Auth bypass in Hyland Pacsgear
CVE-2026-58127
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.
Vulnerability class: Broken Authentication
EPSS: 0.013 (66.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Hyland Pacsgear
- Hyland Pacsgear Mediawriter — versions 5.2.1
Weakness classification (CWE)
References
- disclosure@vulncheck.com (Exploit, technical-description, Third Party Advisory, exploit)
- disclosure@vulncheck.com (Product, product)
- disclosure@vulncheck.com (VDB Entry, Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-58127?
- CVE-2026-58127 is a critical-severity vulnerability in Hyland Pacsgear, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-07-01.
- How severe is CVE-2026-58127?
- Critical severity. CVSS v3 base score is 9.8 out of 10.