CVE-2026-4499Public exploitNetwork attack vector

Unauthenticated command execution via HTTP_ST injection

Published Mar 20, 2026 · Updated Mar 20, 2026

OS command injection in D-Link DIR-820LW 2.03 allows remote attackers to execute commands through an SSDP request. The ssdpcgi_main function places attacker-controlled HTTP_ST environment-variable content into an operating-system command without neutralizing shell metacharacters. No authentication or user interaction is required, so a network-reachable router can run attacker-supplied commands and suffer data or service impact.

CVSS severity9.8
Critical
EPSS probability3.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in D-Link DIR-820LW 2.03 allows remote attackers to execute commands through an SSDP request. The ssdpcgi_main function places attacker-controlled HTTP_ST environment-variable content into an operating-system command without neutralizing shell metacharacters. No authentication or user interaction is required, so a network-reachable router can run attacker-supplied commands and suffer data or service impact.

The record

CVE
CVE-2026-4499
Published
Mar 20, 2026
Updated
Mar 20, 2026
Vendor
D-Link
Product
DIR-820LW
Classifications
CWE-78, CWE-77, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 20, 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=2.03

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

D-Link · DIR-820LWversion=2.03

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
7.3VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
7.5VulDBAV:N/AC:L/Au:N/C:P/I:P/A:P

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-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1059Command and Scripting Interpreter

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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