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PacsgearApplication · Hyland

CVE-2026-58127

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-01
Fix available
A fix is available. Upgrade to after 5.2.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

PACSgear MediaWriter 5.2.1 runs an unauthenticated .NET Remoting TCP service on port 9000 exposing RemoteObj and UIRemoteObj ObjectURIs. Attackers exploit MarshalByRefObject unmarshalling with .NET WebClient methods to read/write arbitrary files. Chaining this with DLL hijacking (CRYPTBASE.DLL load from application directory) when the service runs as NT Authority\SYSTEM yields unauthenticated remote code execution.

MitigationImmediately firewall or block TCP port 9000 at the network boundary; if the service is not required, disable it entirely. Consider adding authentication to the Remoting endpoint or upgrading if vendor provides a patched version.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PacsgearApplication
Affected:<= 5.2.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify PACSgear MediaWriter installation
    Check for the application in Add/Remove Programs (Programs and Features), or look for the installation directory - typically under C:\Program Files\PACSgear or C:\Program Files (x86)\PACSgear. Check the version by right-clicking the executable and viewing Properties > Details.
    Affected if The software is installed and version is 5.2.1 or lower
  2. Confirm port 9000 is listening
    Open Command Prompt and run: netstat -ano | findstr :9000. Also verify with PowerShell: Get-NetTCPConnection -LocalPort 9000
    Affected if Port 9000 shows as LISTENING, indicating the unauthenticated .NET Remoting service is active
  3. Identify the service account
    Open Services.msc, locate the PACSgear MediaWriter service, right-click and select Properties. Check the 'Log On As' field. Alternatively, run: sc qc MediaWriterServiceName (or similar)
    Affected if The service runs as NT Authority\SYSTEM or another privileged account
  4. Verify vulnerable ObjectURIs are exposed
    Use a tool like netcat or PowerShell to connect to port 9000 and inspect the exposed endpoints. The vulnerable URIs are 'RemoteObj' and 'UIRemoteObj'. Check if the .NET Remoting service responds to requests on these endpoints.
    Affected if The service responds with RemoteObj or UIRemoteObj ObjectURIs, confirming the attack surface is exposed
  5. Check for DLL hijacking opportunity
    Navigate to the PACSgear MediaWriter installation directory. Look for the presence of CRYPTBASE.DLL in that folder, or verify the application attempts to load CRYPTBASE.DLL from its own directory (check with Process Monitor for DLL load attempts).
    Affected if CRYPTBASE.DLL exists in the application directory or the app loads DLLs from that path without secure resolution

A user is affected if PACSgear MediaWriter version 5.2.1 or lower is installed, port 9000 is actively listening, and the service runs with elevated privileges, exposing the unauthenticated .NET Remoting endpoints to exploitation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 5.2.1
Interim mitigation

Immediately firewall or block TCP port 9000 at the network boundary; if the service is not required, disable it entirely. Consider adding authentication to the Remoting endpoint or upgrading if vendor provides a patched version.

Fix this in Pacsgear Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-58127 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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