CVE-2025-15559: Unauthenticated OS Command Injection in NesterSoft WorkTime

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-19 · updated 2026-06-17
Weakness: CWE-78

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.

Affected products

NesterSoft Inc. WorkTime (on-prem/cloud): through 11.8.8

References

https://r.sec-consult.com/worktime

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