CVE-2019-20500
D-Link DWL-2600AP Access Point Command Injection Vulnerability
Description
CVE-2019-20500 is an authenticated OS command injection vulnerability in the D-Link DWL-2600AP access point running firmware version 4.2.0.15 Rev A. The vulnerability exists in the Save Configuration functionality of the web management interface, where an attacker with administrative access can inject arbitrary operating system commands through shell metacharacters in the configBackup or downloadServerip parameters of the admin.cgi endpoint. While exploitation requires authentication, successful command injection on the D-Link DWL-2600AP grants the attacker full system-level control over the access point. CISA has added CVE-2019-20500 to the Known Exploited Vulnerabilities catalog, and the EPSS score of 92.2% (99th percentile) indicates near-certain exploitation activity.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| dlink | dwl-2600ap firmware | <= 4.2.0.15 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10113(Patch, Vendor Advisory)
- https://www.exploit-db.com/exploits/46841(Exploit, Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-20500(US Government Resource)
Weakness Type
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
In CVE-2019-20500, the D-Link DWL-2600AP web interface passes user-supplied input from the Save Configuration form directly to operating system commands without proper sanitization. The configBackup and downloadServerip parameters in admin.cgi accept shell metacharacters that allow an authenticated administrator to inject and execute arbitrary commands on the underlying operating system.
Learn more: CWE-78 — Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Impact Analysis
CVE-2019-20500 carries a CVSS v3.1 score of 7.8 (High), reflecting the serious consequences of successful exploitation despite the authentication requirement. The vulnerability is exploitable locally with low attack complexity and requires only low privileges — once an attacker has authenticated access to the DWL-2600AP management interface, no additional user interaction is needed. Confidentiality, integrity, and availability are all rated High, meaning the attacker can read sensitive configuration data including wireless credentials and network settings, modify the device's configuration to create persistent backdoors, and disrupt network services for all connected clients. The EPSS score of 92.2% places this vulnerability in the 99th percentile, indicating that exploitation is near-certain and actively occurring. Organizations using the DWL-2600AP in enterprise wireless deployments face the additional risk of the compromised access point being used as a pivot point for lateral movement within the internal network.
Exploit Maturity
Public exploit code is available for CVE-2019-20500 via Exploit-DB, providing a ready-to-use proof of concept that demonstrates the OS command injection through the admin.cgi endpoint. CISA has confirmed active exploitation in the wild by including this vulnerability in the Known Exploited Vulnerabilities catalog with a remediation deadline of July 20, 2023. The EPSS score of 92.2% (99th percentile) indicates near-certain exploitation activity, consistent with the availability of public exploit code and the widespread deployment of DWL-2600AP access points in enterprise environments. The ransomware association is currently listed as unknown.
Remediation
- Apply vendor patches immediately as directed by CISA: apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. D-Link has released a security advisory SAP10113 with updated firmware.
- Update the D-Link DWL-2600AP firmware to the latest version available from D-Link's support portal that addresses the command injection vulnerability in admin.cgi. Verify the firmware version after installation to confirm the patch was successfully applied.
- Restrict management interface access by ensuring the DWL-2600AP web administration interface is only accessible from a dedicated management VLAN or specific administrator IP addresses. Disable remote management over WAN interfaces and enforce strong, unique administrative credentials to limit the authenticated attack vector.
- Monitor access point logs for unusual administrative actions, particularly configuration save operations with suspicious parameter values containing shell metacharacters (such as semicolons, pipes, or backticks) in the configBackup or downloadServerip fields.
- Replace end-of-life DWL-2600AP units with actively supported access point models if D-Link has discontinued firmware updates for this product, as OS command injection vulnerabilities in legacy firmware represent a persistent and unmitigable risk.
Technical Details
CVE-2019-20500 is an OS command injection vulnerability (CWE-78) in the D-Link DWL-2600AP's web-based management interface, specifically in the configuration save functionality handled by admin.cgi. When an authenticated administrator triggers the action=config_save operation, the server-side CGI script constructs operating system commands using the configBackup and downloadServerip parameters without properly sanitizing or escaping shell metacharacters. An attacker with valid administrative credentials can inject arbitrary commands by including characters such as semicolons, backticks, or pipe operators in these parameters, which are then executed in the context of the web server process. The CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) classifies this as a local attack vector with low complexity and low privilege requirements, though in practice exploitation occurs through the web interface using stolen or default administrative credentials, resulting in complete compromise of the access point's confidentiality, integrity, and availability.
Frequently Asked Questions
Is CVE-2019-20500 being actively exploited?
Yes, CISA has confirmed active exploitation of CVE-2019-20500 by including it in the Known Exploited Vulnerabilities catalog with a remediation deadline of July 20, 2023. The EPSS score of 92.2% (99th percentile) further confirms near-certain exploitation activity. Public exploit code is available on Exploit-DB, making it accessible to a wide range of attackers.
What products are affected by CVE-2019-20500?
CVE-2019-20500 specifically affects the D-Link DWL-2600AP wireless access point running firmware version 4.2.0.15 Rev A. The vulnerability is in the web management interface's configuration save functionality, and other firmware versions of the DWL-2600AP may also be affected.
How do I fix CVE-2019-20500?
The recommended fix is to update the DWL-2600AP firmware to the patched version referenced in D-Link's security advisory SAP10113. As an interim mitigation, restrict access to the management interface to trusted administrator IP addresses only and ensure strong, unique administrative credentials are in use. If the device is end of life, consider replacing it with a supported model.
How severe is CVE-2019-20500?
CVE-2019-20500 has a CVSS v3.1 score of 7.8, rated as High severity. While exploitation requires authenticated access to the management interface, the attack complexity is low and results in complete system compromise. The EPSS score of 92.2% places it in the 99th percentile, confirming it is among the most likely vulnerabilities to be exploited.
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