CVE-2025-62404: TP-Link Archer AX53 Buffer Overflow Flaw

CVE-2025-62404 Overview

CVE-2025-62404 is a heap-based buffer overflow vulnerability affecting the TP-Link Archer AX53 v1.0 router, specifically within the tmpserver modules. This firmware vulnerability allows authenticated attackers with adjacent network access to cause a segmentation fault or potentially execute arbitrary code by sending specially crafted network packets that exceed the maximum expected length.

Critical Impact

Authenticated attackers on the local network can exploit this heap-based buffer overflow to crash the router or potentially achieve remote code execution, compromising network security and device integrity.

Affected Products

• TP-Link Archer AX53 v1.0 firmware through version 1.3.1 Build 20241120
• Devices running vulnerable tmpserver modules
• All Archer AX53 v1 devices without the latest security patch

Discovery Timeline

• 2026-02-03 - CVE-2025-62404 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2025-62404

Vulnerability Analysis

This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), a memory corruption flaw that occurs when data is written beyond the boundaries of an allocated heap buffer. In the context of the TP-Link Archer AX53 router, the tmpserver modules fail to properly validate the length of incoming network packets before processing them. When an attacker sends a packet with a length exceeding the maximum expected value, the overflow corrupts adjacent heap memory structures.

The exploitation requires the attacker to be authenticated and have adjacent network access, meaning they must be on the same local network segment as the vulnerable device. While this limits the attack surface compared to remotely exploitable vulnerabilities, it remains a significant risk in environments where attackers can gain initial network access through other means such as compromised Wi-Fi credentials or physical access.

Root Cause

The root cause of this vulnerability lies in insufficient bounds checking within the tmpserver modules when handling network packet lengths. The firmware does not adequately validate that incoming packet data fits within the allocated heap buffer before copying it, allowing attackers to write beyond the intended memory boundary. This classic heap overflow pattern can corrupt heap metadata, function pointers, or adjacent data structures.

Attack Vector

The attack requires the adversary to have authenticated access to the local network where the Archer AX53 router is deployed. The attacker crafts a malicious network packet with a length field that exceeds what the tmpserver module expects. When this oversized packet is processed, the excess data overwrites adjacent heap memory, potentially leading to:

1. Denial of Service: A segmentation fault causing the router to crash or become unresponsive
2. Code Execution: Carefully crafted overflow data could overwrite heap metadata or function pointers to redirect execution flow

The vulnerability mechanism involves sending specially crafted network packets to the tmpserver modules with oversized length values. The modules allocate a fixed-size heap buffer based on expected maximum packet lengths, but fail to validate that incoming data conforms to these limits. For detailed technical information, refer to the Talos Intelligence Vulnerability Reports and the TP-Link Security FAQ.

Detection Methods for CVE-2025-62404

Indicators of Compromise

• Unexpected router crashes, reboots, or unresponsive behavior on Archer AX53 devices
• Anomalous network traffic patterns originating from adjacent devices targeting the router management interfaces
• Unusual heap-related error messages or segmentation faults in router system logs
• Unauthorized configuration changes or unexpected firmware modifications

Detection Strategies

• Monitor network traffic for oversized or malformed packets targeting TP-Link router management services
• Implement network segmentation to limit adjacent network attack surfaces
• Deploy network intrusion detection systems (NIDS) with rules for detecting buffer overflow exploitation attempts
• Review router logs for repeated crash events or memory-related errors

Monitoring Recommendations

• Enable logging on the Archer AX53 router and export logs to a centralized SIEM for analysis
• Monitor for devices exhibiting repeated crash-reboot cycles which may indicate active exploitation attempts
• Track firmware versions across all network devices to identify unpatched Archer AX53 routers
• Implement network access control to monitor and alert on new devices joining the local network segment

How to Mitigate CVE-2025-62404

Immediate Actions Required

• Update TP-Link Archer AX53 v1 firmware to a version newer than 1.3.1 Build 20241120 as soon as a patch is available
• Restrict network access to trusted devices only using MAC filtering or network segmentation
• Change default administrative credentials and use strong, unique passwords for router authentication
• Monitor the router for unusual behavior or unexpected reboots

Patch Information

TP-Link has acknowledged this vulnerability. Users should check the TP-Link Archer AX53 Firmware Download page for the latest security updates. It is critical to apply firmware updates as soon as they become available. Additional security guidance can be found in the TP-Link Security FAQ.

Workarounds

• Enable strict network segmentation to isolate the Archer AX53 from untrusted devices
• Limit administrative access to the router by disabling remote management and restricting management interface access to specific trusted IPs
• Implement additional network monitoring to detect anomalous traffic patterns targeting the router
• Consider deploying a firewall in front of the router to filter potentially malicious packets

# Network segmentation example for isolating IoT/router management
# Create a separate VLAN for router management access
# This limits the adjacent network attack surface

# Example: Configure firewall to restrict access to router management ports
iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP