RCE in Zend Zendto

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 attackers to execute arbitrary commands via shell metacharacters in the tmp_name parameter when dropping off a file via a POST /dropoff request.

Vulnerability class: Command Injection (OS Command Injection)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.366 (98.4th percentile), scored .

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 98.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-47667: rose from 0.331 to 0.366.

EPSS over last 30 days · oldest: 0.331 · newest: 0.366 · change: +0.035

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-47667?
CVE-2021-47667 is a critical-severity vulnerability in Zend Zendto, classified under OS Command Injection. CVSS score: 10.0/10. Published 2025-04-05.
How severe is CVE-2021-47667?
Critical severity. CVSS v3 base score is 10.0 out of 10.