CVE-2026-25551
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 · uneditedSeagull Software BarTender 2021 R1 through 12.0.1 contains an insecure deserialization vulnerability that allows low-privileged local users to escalate privileges. The DataServiceSingleton .NET Remoting endpoint is bound to localhost on TCP port 7375 via BtSystem.Service.exe, limiting the attack surface to local access only. The endpoint is configured with BinaryServerFormatterSinkProvider and TypeFilterLevel set to Full. A low-privileged local attacker can send YSoSerial.NET-generated BinaryFormatter payloads to the localhost-bound endpoint to achieve code execution as NT AUTHORITY\\SYSTEM.
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 confidenceBarTender's DataServiceSingleton .NET Remoting endpoint on localhost:7375 uses BinaryServerFormatterSinkProvider with TypeFilterLevel set to Full, allowing deserialization of arbitrary .NET types. A low-privileged local attacker can send crafted BinaryFormatter payloads via YSoSerial.NET to achieve code execution as NT AUTHORITY\SYSTEM.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed BarTender versionCheck the Windows Registry at HKLM\SOFTWARE\Seagull\BarTender\Version or examine the version property of the BarTender installation directory (typically C:\Program Files\Seagull\BarTender).Affected if The installed version falls within the range 2021 R1 through 12.0.1 (verify against vendor release notes for exact version numbers).
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Verify BtSystem.Service.exe is runningOpen Task Manager or run 'tasklist /FI "IMAGENAME eq BtSystem.Service.exe"' in Command Prompt to check if the service process is active.Affected if BtSystem.Service.exe is currently running on the system.
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Confirm port 7375 is listeningRun 'netstat -ano | findstr :7375' or use PowerShell 'Get-NetTCPConnection -LocalPort 7375' to check if TCP port 7375 is bound and listening.Affected if Port 7375 is in LISTENING state bound to 127.0.0.1 (localhost).
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Check BinaryServerFormatterSinkProvider configurationExamine the BtSystem.Service.exe configuration files in the BarTender installation directory for BinaryServerFormatterSinkProvider with TypeFilterLevel set to Full.Affected if The configuration contains BinaryServerFormatterSinkProvider with TypeFilterLevel="Full" (the vulnerable setting).
A system is affected if it runs a vulnerable BarTender version (2021 R1 through 12.0.1) with BtSystem.Service.exe active and port 7375 listening with the Full TypeFilterLevel configuration.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade to a patched version of BarTender or disable the DataServiceSingleton .NET Remoting service if not required; network isolation provides minimal benefit as the vulnerable endpoint is localhost-bound.
- Consultation4.0 h
- Implementation8.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-25551 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-25551 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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