What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-04 · updated 2026-09-02
• Weakness: CWE-502

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. The vulnerability was corrected in BarTender 12.1, released on August 14, 2026. Users should upgrade to BarTender 12.1 or later.

Affected products

• Seagull Software, LLC. BarTender 2021: from R1 through 12.0.1

References

• https://gist.github.com/VAMorales/dde5b1c0415a8505ccd6fafdb095a618
• https://portal.seagullscientific.com/downloads/bartender
• https://trust.seagullsoftware.com/?tcuUid=55ed135f-683c-4e9b-a59d-7d4373c0ac7e
• https://www.vulncheck.com/advisories/seagull-software-bartender-deserialization-privilege-escalation-via-net-remoting-service

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