Vulnerability · Published Jun 4, 2026 · Assigned by VulnCheck

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

High 7.8

In plain English

A high-severity unsafe deserialization in BarTender 2021 from Seagull Software, LLC.. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities).

Severity (CVSS 3.1)7.8High

Exploit odds (30 days)0.1%top 97.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
Seagull Software, LLC.	BarTender 2021	R1 – through 12.0.1

Weakness: CWE-502 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Vendor Advisory vendor-advisory, patch
Researcher Disclosure technical-description, exploit
Product Page product
https://www.vulncheck.com/advisories/seagull-software-bartender-deserialization-privilege-escalation-via-net-remoting-service third-party-advisory