CVE-2021-4039

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

71.05% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 99.3% of scored records. A rank, not a probability.

NVD base score

9.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2022-03-01 06:40Z4 YR AGO

Last updated

2024-08-03 17:16Z2 YR AGO

Reserved

2021-12-02

Assigning CNA

Zyxel

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

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

Weaknesses

• CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')Base

Data version

5.1

Document digest

278ca82db1470b0bd5b74d2d5ba9313b2e607faa6a433f6d5a1561b5b9f89c9b

• www.zyxel.comhttps://www.zyxel.com/support/OS-command-injection-vulnerability-of-NWA1100-NH-access-point.shtmlx_refsource_CONFIRM
• packetstormsecurity.comhttp://packetstormsecurity.com/files/166752/Zyxel-NWA-1100-NH-Command-Injection.htmlx_refsource_MISC