CVE-2019-20759 in R9000
Summary
by MITRE
NETGEAR R9000 devices before 1.0.4.26 are affected by stored XSS.
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Analysis
by VulDB Data Team • 05/07/2025
The vulnerability CVE-2019-20759 represents a stored cross-site scripting flaw in NETGEAR R9000 wireless routers, specifically impacting firmware versions prior to 1.0.4.26. This issue resides within the web-based management interface of the device, creating a persistent security weakness that allows attackers to inject malicious scripts into the router's configuration pages. The stored nature of this vulnerability means that once malicious code is injected, it persists in the device's memory and executes whenever users access the affected web interface, making it particularly dangerous for network administrators who regularly interact with the router's management console.
The technical flaw stems from insufficient input validation and output sanitization within the router's web application. When administrators or users enter data into certain configuration fields through the web interface, the device fails to properly sanitize this input before storing it in its database or configuration files. This allows malicious actors to embed script code that gets executed in the context of other users' browsers when they navigate to affected pages. The vulnerability specifically affects the router's administrative web interface, where legitimate users expect to see trusted content, but instead encounter malicious payloads that can steal session cookies, redirect users to phishing sites, or perform unauthorized actions on behalf of the authenticated user.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a potential foothold for more sophisticated attacks within the network infrastructure. Network administrators who regularly access the router's management interface become targets for credential theft, session hijacking, and privilege escalation attacks. The stored nature of the XSS vulnerability means that even after the initial injection, the malicious code continues to execute for any user who accesses the affected interface, potentially compromising multiple administrators over time. This creates a persistent threat vector that can remain active for extended periods without detection, particularly in environments where router management is performed infrequently or by multiple personnel.
Organizations should immediately implement firmware updates to version 1.0.4.26 or later, which addresses the input validation deficiencies that enable this vulnerability. Network segmentation and access controls should be enforced to limit administrative access to critical network infrastructure, reducing the attack surface for such vulnerabilities. Regular security audits of network devices should include checks for outdated firmware versions and proper input sanitization practices. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws, and represents a significant concern in the context of the ATT&CK framework under the T1059.007 technique for command and scripting interpreter. Additional mitigations include implementing web application firewalls, conducting regular security assessments of network management interfaces, and establishing robust patch management processes to ensure timely deployment of security updates across all network infrastructure devices.