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Fencer Vulns
critical 9.8

CVE-2021-4039 in the critical feed json

A command injection vulnerability in the web interface of the Zyxel NWA-1100-NH firmware could allow an attacker to execute arbitrary OS co…

published 2022-03-01 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33939

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
71.0%
EPSS 71.0% chance of exploitation in 30 days, percentile 99.4%
public exploits
1
Exploit-DB

Summary

A command injection vulnerability in the web interface of the Zyxel NWA-1100-NH firmware could allow an attacker to execute arbitrary OS commands on the device.

Patch / fix

  • zyxel nwa1100-nh_firmware 2.12\(aasi.3\)c0

Timeline

  1. Published
  2. First public exploit (EDB-50870)

Exploit prediction

71.05% chance of exploitation in the next 30 days, higher than 99.4% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-50870 Zyxel NWA-1100-NH - Command Injection remote, 2022-04-19
  • packetstormsecurity.com http://packetstormsecurity.com/files/166752/Zyxel-NWA-1100-NH-Command-Injection.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • Zyxel NWA1100-NH firmware

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.