Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-4039

78
FAUCET Score

CVE-2021-4039 is a critical command injection vulnerability (CWE-78) in the web interface of Zyxel NWA-1100-NH firmware, allowing unauthenticated attackers to execute arbitrary OS commands. With a CVSS score of 9.8, it presents a severe risk due to its network-based attack vector, low complexity, and complete compromise of confidentiality, integrity, and availability. While not on the CISA KEV catalog, public exploit code exists on ExploitDB, and it has garnered significant community discussion, indicating potential for exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.12\(aasi.3\)c0CPE matchmatch criteria
cpe:2.3:o:zyxel:nwa1100-nh_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
71.05%
Probability of exploitation in next 30 days
EPSS Percentile
99.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
ExploitDB: EDB-50870 · Apr 19, 2022
This CVE's current EPSS score of 0.7105 is in the 98th percentile among its peer group of 36,833 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

packetstormsecurity.com / files/166752/Zyxel-NWA-1100-NH-Command-Injection.html
ExploitRelease NotesThird Party AdvisoryVDB Entry
zyxel.com / support/OS-command-injection-vulnerability-of-NWA1100-NH-access-point.shtml
PatchVendor Advisory