CVE-2020-21016Public exploitNetwork attack vector

Root command execution via unsanitized guest SSID

Published Oct 31, 2022 · Updated May 7, 2025

Command injection in D-Link DIR-846 firmware 100A35 allows remote attackers to execute arbitrary commands as root via a crafted guest SSID. The SetGuestWLanSettings.php handler places wl(0).(1)_ssid and wl(1).(1)_ssid values directly inside single-quoted arguments passed to PHP exec(), without neutralizing shell metacharacters. Network access to the HNAP endpoint is required; successful injection provides unrestricted root-level command execution on the router.

CVSS severity9.8
Critical
EPSS probability2.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Command injection in D-Link DIR-846 firmware 100A35 allows remote attackers to execute arbitrary commands as root via a crafted guest SSID. The SetGuestWLanSettings.php handler places wl(0).(1)_ssid and wl(1).(1)_ssid values directly inside single-quoted arguments passed to PHP exec(), without neutralizing shell metacharacters. Network access to the HNAP endpoint is required; successful injection provides unrestricted root-level command execution on the router.

The record

CVE
CVE-2020-21016
Published
Oct 31, 2022
Updated
May 7, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 31, 2022CVE publishedPublication date reported by the CVE source.
  2. May 7, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo