NETGEAR JGS516PE Missing Function-Level Access Control Vulnerability (CVE-2020-26919) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTNETGEAR JGS516PE devices running firmware versions prior to 2.6.0.43
Unauthenticated remote attackers can bypass authentication to access sensitive management functions, potentially leading to arbitrary command execution and full device compromise
Immediately upgrade the JGS516PE firmware to version 2.6.0.43 or later and restrict access to the management interface
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
To remediate this vulnerability, administrators must upgrade the JGS516PE firmware to version 2.6.0.43 or higher. While firmware upgrades are typically performed via the Web GUI, the following commands illustrate how to verify system status and prepare for maintenance.
# Verify current system information and firmware version via CLI (if supported by configuration)
show system information
# Example of downloading the secure firmware image via TFTP in a staging environment
tftp -g -r JGS516PE_V2.6.0.43.bin 192.168.0.1002. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, restrict access to the switch's management interface using firewall rules or Access Control Lists (ACLs) to ensure only authorized administrator IPs can connect.
# Restrict access to the switch's web interface (ports 80/443) to a trusted admin IP (e.g., 192.168.1.50) using iptables
iptables -A INPUT -p tcp -s 192.168.1.50 --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.1.50 --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP3. Log Audit & IoC Verification Commands
Inspect web server access logs and network traffic for unauthorized POST requests directed at configuration endpoints or CGI scripts without prior successful authentication.
# Scan the local subnet to identify active JGS516PE web interfaces
nmap -p 80,443 --script http-title 192.168.1.0/24
# Search web server logs for suspicious unauthenticated POST requests to administrative endpoints
grep -E 'POST /(cgi-bin/|apply\.cgi|config)' /var/log/nginx/access.log | grep -v '200'Stop Exposing VPN Ports to the Internet — Switch to Zero-Trust Access
Eliminate public-facing VPN concentrators and firewall management ports with identity-first Zero-Trust Network Access.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2020-26919) is a critical missing function-level access control issue (CWE-862) within the web management interface of NETGEAR JGS516PE switch devices. The root cause lies in the application's failure to perform proper authorization checks when handling requests to specific administrative endpoints. Consequently, an attacker can directly invoke sensitive functions without establishing a valid authenticated administrator session.
2. Exploitation Mechanics & Attack Scenario
An attacker scans the network to locate the web management interface of a vulnerable JGS516PE switch. By crafting direct HTTP GET or POST requests to internal CGI scripts or configuration endpoints (bypassing the login page), the attacker can execute administrative tasks. When combined with input validation flaws, this can allow the execution of arbitrary system commands on the underlying operating system. Due to its high reliability and impact, this vulnerability has been actively exploited in the wild and is listed in the CISA KEV catalog.
3. Infrastructure & Business Impact
The JGS516PE is a widely deployed PoE+ Gigabit Smart Managed Plus switch in SMB and branch office environments. Compromising this device allows attackers to intercept network traffic, manipulate VLAN configurations to bypass network segmentation, or use the switch as a persistent pivot point to launch further attacks against internal servers and endpoints, posing a severe threat to business operations and data confidentiality.
Official Vendor Advisories & References
NETGEAR JGS516PE devices before 2.6.0.43 are affected by lack of access control at the function level.
Frequently Asked SecOps Questions (CVE-2020-26919)
FAQQ1. How critical is CVE-2020-26919 and is it actively exploited in the wild?
CVE-2020-26919 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 57.5%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2020-26919?
Primary impacted vendors include netgear across jgs516pe. Scope summary: All NETGEAR JGS516PE devices with firmware versions prior to 2.6.0.43
Q3. What temporary mitigations or workarounds exist for CVE-2020-26919 before patching?
[Mitigation] Immediately upgrade the JGS516PE firmware to version 2.6.0.43 or later and restrict access to the management interface Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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