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

> Unauthenticated attackers can execute arbitrary OS commands with SYSTEM privileges via the guid parameter in the WorkTime server API.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-p5gf-vhgm-432f

## What is CVE-2025-15559?

CVE-2025-15559 is a critical command injection vulnerability in NesterSoft Inc. WorkTime (on-prem/cloud), published on 19 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2025-15559?

It affects 1 product.


Products: Nestersoft Worktime.

## How do I fix CVE-2025-15559?

No fix has been published for CVE-2025-15559 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-15559 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-15559 exists.

## Other vulnerabilities in NesterSoft Inc. WorkTime (on-prem/cloud)

- [CVE-2025-15560](https://insights.sbomify.com/CVE-2025-15560/): SQL Injection in NesterSoft WorkTime (high 8.8)
- [CVE-2025-15561](https://insights.sbomify.com/CVE-2025-15561/): Local Privilege Escalation in NesterSoft WorkTime (high 7.8)
- [CVE-2025-15562](https://insights.sbomify.com/CVE-2025-15562/): Reflected Cross-Site Scripting in NesterSoft WorkTime (medium 6.1)
- [CVE-2025-15563](https://insights.sbomify.com/CVE-2025-15563/): Broken Access Control results in Denial of Service in NesterSoft WorkTime (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-15559 and fix it if it is affected.

What it is: CVE-2025-15559 is a critical command injection vulnerability in NesterSoft Inc. WorkTime (on-prem/cloud), published on 19 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-15559 exists.

Affected product: NesterSoft Inc. WorkTime (on-prem/cloud). No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-15559/ (Markdown: https://insights.sbomify.com/CVE-2025-15559/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-15559
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-15559
- OSV: https://osv.dev/vulnerability/CVE-2025-15559

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-15559/
Summaries are generated and may contain mistakes; the official description above is the record.