Cyber Resilience

CVE-2025-25427

HighPublic PoC

Published: 18 April 2025

Published
18 April 2025
Modified
09 July 2025
KEV Added
Patch
CVSS Score v4 8.6 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:N/SA:L/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
EPSS Score 0.0224 84.9th percentile
Risk Priority 19 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-25427 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Tp-Link Wr841N. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 15.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis

A stored cross-site scripting vulnerability exists in the upnp.htm page of the web management interface on TP-Link WR841N routers running firmware versions v14, v14.6, and v14.8 up to build 241230 Rel. 50788n. The flaw, tracked as CWE-79, permits arbitrary JavaScript injection through the port mapping description field and causes the payload to execute whenever an authenticated user loads the UPnP configuration page. The issue carries a CVSS 4.0 score of 8.6.

An attacker with adjacent-network access can supply a malicious description when creating or editing a port mapping entry. When a legitimate administrator subsequently views the UPnP page, the injected script runs in the administrator’s browser context, enabling theft of session cookies, configuration changes, or other actions within the router’s web interface.

TP-Link has published updated firmware images and a security FAQ on its support site that address the affected hardware revisions. Administrators should verify the latest available builds for the WR841N and apply them according to the vendor’s instructions; the referenced GitHub repository contains additional technical details and proof-of-concept material for validation after patching. The associated EPSS score remains low and unchanged at 0.0224.

EU & UK References

Vulnerability details

A stored cross-site scripting (XSS) vulnerability in the upnp.htm page of the web Interface in TP-Link WR841N v14/v14.6/v14.8 <= Build 241230 Rel. 50788n allows remote attackers to inject arbitrary JavaScript code via the port mapping description. This leads to an…

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execution of the JavaScript payload when the upnp page is loaded.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
T1602.002 Network Device Configuration Dump Collection
Adversaries may access network configuration files to collect sensitive data about the device and the network.
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
Why these techniques?

Stored XSS via UPnP port mapping description enables unauthenticated arbitrary JS execution in authenticated admin browser context on router web interface, facilitating public-facing app exploitation (T1190), web session cookie theft (T1539), network device config dump (T1602.002), and content injection (T1659).

Affected Assets

tp-link
wr841n firmware
≤ 241230

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References