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Description

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.

PUBLISHED Reserved 2026-02-02 | Published 2026-06-04 | Updated 2026-06-08 | Assigner VulnCheck




HIGH: 8.5CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

HIGH: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem types

CWE-502 Deserialization of Untrusted Data

Product status

Default status
affected

R1 (custom)
affected

Credits

Victor A. Morales, Senior Pentester Team Leader, GM Sectec, Corp. finder

Jan A. Rodriguez, Pentester, GM Sectec, Corp. finder

VulnCheck finder

References

gist.github.com/VAMorales/dde5b1c0415a8505ccd6fafdb095a618 technical-description exploit

portal.seagullscientific.com/downloads/bartender product

www.vulncheck.com/...ege-escalation-via-net-remoting-service third-party-advisory

cve.org (CVE-2026-25551)

nvd.nist.gov (CVE-2026-25551)

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