CVE-2023-39637Public exploitNetwork attack vector

Remote command execution via unfiltered sendNum parameter

Published Sep 12, 2023 · Updated Jul 9, 2026

Command injection in D-Link DIR-816 A2 1.10 B05 allows remote attackers to execute arbitrary commands through the diagnostic interface. The /goform/Diagnosis handler inserts the sendNum parameter into a command string with snprintf and passes it to system() without neutralizing shell syntax. Network access to the management interface is sufficient; the published proof of concept retrieves a token without credentials and reboots the router.

CVSS severity9.8
Critical
EPSS probability2.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in D-Link DIR-816 A2 1.10 B05 allows remote attackers to execute arbitrary commands through the diagnostic interface. The /goform/Diagnosis handler inserts the sendNum parameter into a command string with snprintf and passes it to system() without neutralizing shell syntax. Network access to the management interface is sufficient; the published proof of concept retrieves a token without credentials and reboots the router.

The record

CVE
CVE-2023-39637
Published
Sep 12, 2023
Updated
Jul 9, 2026
Vendor
D-Link
Product
DIR-816
Classifications
CWE-77, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.10_b05

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

D-Link · DIR-816version=1.10_b05

Published CVSS scores

9.8NVDCVSS: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.

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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-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1190Exploit Public-Facing Application

Public exploit references

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

Technologies

Your stack

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Your stack

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