EUVD-2025-208944
GHSA-7gjx-r4jj-vjx7
CVSS Vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4Tags
Description
A Denial-of-Service (DoS) vulnerability in the httpd component of TP-Link's TD-W8961N v4.0 due to improper input sanitization, allows crafted requests to trigger a processing error that causes the httpd service to crash. Successful exploitation may allow the attacker to cause service interruption, resulting in a DoS condition.
Analysis
A Denial-of-Service vulnerability exists in the httpd component of TP-Link TD-W8961N v4.0 routers, caused by improper input sanitization (CWE-20) that allows attackers to craft malicious requests triggering httpd service crashes. The vulnerability enables service interruption and network unavailability for affected users. Although no CVSS score or EPSS metric is publicly available, a vendor patch is already available, indicating acknowledgment of the issue's severity and exploitability.
Technical Context
The vulnerability resides in the httpd (HTTP daemon) web service component of TP-Link's TD-W8961N wireless ADSL router (CPE: cpe:2.3:a:tp-link_systems_inc.:td-w8961n_v4.0:*:*:*:*:*:*:*:*). The root cause is classified as CWE-20 (Improper Input Validation), meaning the httpd service fails to properly sanitize or validate incoming HTTP request data before processing. When specially crafted requests are submitted, they bypass input validation checks and trigger an unhandled processing error within the daemon, leading to immediate service termination. This is a common vulnerability pattern in embedded device firmware where lightweight HTTP servers lack robust input handling mechanisms.
Affected Products
TP-Link TD-W8961N v4.0 is the affected product, identified via CPE cpe:2.3:a:tp-link_systems_inc.:td-w8961n_v4.0:*:*:*:*:*:*:*:*. The TD-W8961N is a wireless ADSL combination router and modem commonly deployed in residential and small-business environments. The vulnerability is specific to version 4.0; earlier and later firmware versions may have different vulnerability status. Affected users can verify their device version through the device's web administration interface or physical label. See TP-Link's support page at https://www.tp-link.com/en/support/download/td-w8961n/v4/#Firmware for firmware download details and the FAQ at https://www.tp-link.com/us/support/faq/5028/ for additional information.
Remediation
Immediately upgrade the affected TP-Link TD-W8961N v4.0 router firmware to the latest patched version available from the official TP-Link download portal (https://www.tp-link.com/en/support/download/td-w8961n/v4/#Firmware). The patching process typically involves downloading the firmware image, accessing the device's web administration panel, and performing a firmware upgrade operation; the device will reboot automatically. Until patching is completed, temporarily mitigate risk by disabling remote web administration (ensure the httpd service only listens on the local LAN IP, not the WAN interface) and restricting administrative access via ACLs or firewall rules to trusted IP ranges only. Alternatively, if the router remains behind a carrier-grade NAT or corporate firewall that blocks unsolicited inbound connections, the risk is substantially reduced; however, patching should not be delayed indefinitely. Consult TP-Link's FAQ (https://www.tp-link.com/us/support/faq/5028/) for additional guidance specific to this vulnerability.
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