Vulnerability · Published Feb 19, 2026 · Assigned by SEC-VLab

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

Critical 9.8

In plain English

A critical-severity OS command injection in WorkTime (on-prem/cloud) from NesterSoft Inc.. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.5%top 56.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
NesterSoft Inc.	WorkTime (on-prem/cloud)	<= 11.8.8

Weakness: CWE-78 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://r.sec-consult.com/worktime third-party-advisory