An unauthenticated attacker can inject OS commands when calling a server API endpoint in NesterSoft WorkTime. The server API call to generate and download the WorkTime client from the WorkTime server is vulnerable in the “guid” parameter. This allows an attacker to execute arbitrary commands on the WorkTime server as NT Authority\SYSTEM with the highest privileges. Attackers are able to access or manipulate sensitive data and take over the whole server.

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Fixes

Solution

The vendor did not respond to our communication attempts anymore. It is currently as of February 2026 unclear, whether a patch is available. Please contact the vendor to request a patch for the identified critical security issues.


Workaround

No workaround given by the vendor.

References
History

Mon, 23 Feb 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 20 Feb 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Nestersoft
Nestersoft worktime
Vendors & Products Nestersoft
Nestersoft worktime

Thu, 19 Feb 2026 11:15:00 +0000

Type Values Removed Values Added
Description An unauthenticated attacker can inject OS commands when calling a server API endpoint in NesterSoft WorkTime. The server API call to generate and download the WorkTime client from the WorkTime server is vulnerable in the “guid” parameter. This allows an attacker to execute arbitrary commands on the WorkTime server as NT Authority\SYSTEM with the highest privileges. Attackers are able to access or manipulate sensitive data and take over the whole server.
Title Unauthenticated OS Command Injection in NesterSoft WorkTime
Weaknesses CWE-78
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: SEC-VLab

Published:

Updated: 2026-02-23T18:30:52.019Z

Reserved: 2026-02-04T07:44:28.922Z

Link: CVE-2025-15559

cve-icon Vulnrichment

Updated: 2026-02-23T18:30:44.904Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-02-19T11:15:55.423

Modified: 2026-02-23T19:22:52.947

Link: CVE-2025-15559

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-02-20T10:07:18Z

Weaknesses