Seagull Software BarTender Deserialization Privilege Escalation via .NET Remoting Service
CVE-2026-25551

8.5HIGH

Key Information:

Vendor

Seagull Software, Llc.

Status
Bartender 2021
Vendor
CVE Published:
4 June 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-25551?

Seagull 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.

Affected Version(s)

BarTender 2021 R1 <= 12.0.1

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-25551 - Proof of Concept

References

https://gist.github.com/VAMorales/dde5b1c0415a8505ccd6faf...
technical-descriptionexploit
https://portal.seagullscientific.com/downloads/bartender
product
https://www.vulncheck.com/advisories/seagull-software-bar...
third-party-advisory

CVSS V4

Score:
8.5
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Victor A. Morales, Senior Pentester Team Leader, GM Sectec, Corp.
Jan A. Rodriguez, Pentester, GM Sectec, Corp.
VulnCheck
.