TP-Link TL Wr940n Vulnerabilities
20 known CVEs, 1 critical, 2 in CISA's Known Exploited Vulnerabilities catalog. Last updated 2026-10-24.
Known CVEs
TP-Link TL-WR940N V4 was discovered to contain a buffer overflow via the ipStart parameter at /userRpm/WanDynamicIpV6CfgRpm. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted GET req...
TP-Link TL-WR940N is vulnerable to a stack-based buffer overflow, caused by improper bounds checking by the ipAddrDispose function. By sending specially crafted ICMP echo request packets, a remote authenticated attack...
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of TP-Link TL-WR940N 3.20.1 Build 200316 Rel.34392n (5553) routers. Authentication is not required to exploit th...
This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of TP-Link TL-WR940N 6_211111 3.20.1(US) routers. Authentication is not required to exploit this vulnerability. T...
TP-Link TL-WR940N V2/V4, TL-WR841N V8/V10, and TL-WR740N V1/V2 was discovered to contain a command injection vulnerability via the component /userRpm/WlanNetworkRpm .
TP-Link TL-WR940N V2/V4, TL-WR841N V8/V10, and TL-WR740N V1/V2 was discovered to contain a buffer overflow via the component /userRpm/WlanMacFilterRpm.
TP-Link TL-WR940N V2/V4, TL-WR841N V8/V10, and TL-WR740N V1/V2 was discovered to contain a buffer overflow via the component /userRpm/FixMapCfgRpm.
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of TP-Link TL-WR940N 3.20.1 Build 200316 Rel.34392n (5553) routers. Authentication is required to exploit this v...
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of TP-Link TL-WR940N 3.20.1 Build 200316 Rel.34392n (5553) routers. Authentication is required to exploit this v...
TP-Link TL-WR940N V3 and V4 with firmware 3.16.9 and earlier contain a buffer overflow via the dnsserver1 and dnsserver2 parameters at /userRpm/Wan6to4TunnelCfgRpm.htm. This vulnerability allows an authenticated attac...
Commonly exposed ports
- Port 23 (Telnet) — Sends admin credentials unencrypted — a common target on older router firmware.
- Port 80 (HTTP admin panel) — The web admin UI; dangerous if remote/WAN administration is left enabled.
- Port 7547 (TR-069 (CWMP)) — ISP remote-management protocol — has been the entry point for several router botnets.
- Port 1900 (UPnP/SSDP) — Lets apps on your LAN open firewall holes automatically, sometimes without your knowledge.
Default credentials
From ProbeShield's own tested default-credential list (see probeshield.com/default-passwords/): "admin" / "tplink" or "admin" / "admin123" over HTTP.
Hardening checklist
- Disable remote (WAN-side) administration unless you specifically need it.
- Turn off UPnP unless a specific app you trust requires it.
- Turn off WPS — it can let an attacker bypass your Wi-Fi password.
- Change the default admin username and password to something unique.
- Check for a firmware update in the router’s admin panel and apply it.
- Disable Telnet/SSH management access if you don’t actively use it.
Frequently asked questions
Is my TP-Link TL Wr940n affected by these vulnerabilities? Only if you’re running a firmware version in the affected range listed above and haven’t updated. Check your router's admin panel for its current firmware version and compare it against the ranges below.
How do I update my TP-Link TL Wr940n's firmware? Log into the router's web admin panel (usually at its local IP address) and look for a Firmware Update or System Update section, or use the vendor's mobile app if it has one.
Does ProbeShield fix these vulnerabilities for me? No — ProbeShield scans your network and tells you what it finds (open ports, default credentials, outdated firmware signals) so you know what to fix, and how. It never changes your devices’ settings.
Sources: National Vulnerability Database (NVD), CISA Known Exploited Vulnerabilities Catalog. This page lists which firmware versions are affected — it doesn't claim your specific unit is vulnerable. Check your device's current firmware version in its admin panel and compare it against the ranges above.