CVE-2026-25551Public exploit

SYSTEM privilege escalation via BinaryFormatter deserialization

Published Jun 4, 2026 · Updated Jun 4, 2026

Insecure deserialization in Seagull Software BarTender 2021 R1 through 12.0.1 allows local users to execute code as NT AUTHORITY\SYSTEM. The localhost DataServiceSingleton endpoint in BtSystem.Service.exe accepts BinaryFormatter payloads with TypeFilterLevel set to Full. Low-privileged local access is sufficient to submit a crafted payload and elevate execution to the SYSTEM account.

CVSS severity8.5
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Insecure deserialization in Seagull Software BarTender 2021 R1 through 12.0.1 allows local users to execute code as NT AUTHORITY\SYSTEM. The localhost DataServiceSingleton endpoint in BtSystem.Service.exe accepts BinaryFormatter payloads with TypeFilterLevel set to Full. Low-privileged local access is sufficient to submit a crafted payload and elevate execution to the SYSTEM account.

The record

CVE
CVE-2026-25551
Published
Jun 4, 2026
Updated
Jun 4, 2026
Vendor
Seagull Software, LLC
Product
BarTender
Classifications
CWE-502, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=R1 <=12.0.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Seagull Software, LLC · BarTenderversion=R1 <=12.0.1

Published CVSS scores

8.5VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.8VulnCheckCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo