CVE-2026-58127 PACSgear MediaWriter 5.2.1 Unauthenticated RCE via .NET Remoting TCP Service
Unauthenticated attackers can achieve remote code execution as SYSTEM via insecure .NET Remoting deserialization in PACSgear MediaWriter.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58127?
CVE-2026-58127 is a critical unsafe deserialization vulnerability in Hyland PACSgear MediaWriter, published on 1 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-58127?
It affects 1 product.
Products include Hyland Pacsgear.
How do I fix CVE-2026-58127?
No fix has been published for CVE-2026-58127 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-58127 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58127 exists.
Other vulnerabilities in Hyland PACSgear MediaWriter
Sources
Also known as GHSA-9h7v-mf98-p6r6.