CVE-2025-61983: TP-Link Archer AX53 Buffer Overflow Flaw

CVE-2025-61983 Overview

A heap-based buffer overflow vulnerability exists in the TP-Link Archer AX53 v1.0 router, specifically within the tmpserver modules. This security flaw allows authenticated adjacent attackers to trigger a segmentation fault or potentially achieve arbitrary code execution by sending specially crafted network packets containing an excessive number of fields with zero-length values.

Critical Impact

Authenticated attackers on the adjacent network can exploit this heap overflow to crash the device or potentially execute arbitrary code, compromising network security and device integrity.

Affected Products

• TP-Link Archer AX53 v1.0 (firmware through 1.3.1 Build 20241120)
• TP-Link Archer AX53 v1.0 tmpserver modules

Discovery Timeline

• 2026-02-03 - CVE CVE-2025-61983 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2025-61983

Vulnerability Analysis

This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), a memory corruption issue that occurs when data is written beyond the allocated heap buffer boundaries. The vulnerability resides in the tmpserver modules of the TP-Link Archer AX53 router firmware. When processing network packets, the modules fail to properly validate the number and length of fields within incoming data structures, allowing attackers to overflow heap memory allocations.

The attack requires adjacency to the target network (physical or logical proximity) and authenticated access to the device. Once these prerequisites are met, an attacker can craft malicious packets with an excessive number of zero-length field values that overwhelm the buffer allocation logic, leading to heap memory corruption.

Root Cause

The root cause of this vulnerability is improper bounds checking in the tmpserver modules when handling incoming network packet fields. The firmware does not adequately validate the count of fields or properly handle edge cases where fields contain zero-length values. This allows a malicious actor to submit packets with an abnormally high number of empty fields, causing the heap buffer to overflow as the parsing logic attempts to process each field without sufficient memory allocation.

Attack Vector

The attack vector is adjacent network-based, meaning the attacker must have access to the same network segment as the vulnerable router. The attack requires authentication, but once authenticated, the attacker can send specially crafted network packets to the tmpserver service. These packets contain an excessive number of fields populated with zero-length values, which triggers the heap overflow condition. Depending on the heap layout and memory state, this can result in a denial of service through segmentation fault or potentially allow arbitrary code execution if the attacker can control the overwritten memory contents.

The exploitation mechanism involves crafting network packets that deliberately abuse the field parsing logic by including numerous zero-length values, forcing the heap allocation to overflow and corrupt adjacent memory structures.

Detection Methods for CVE-2025-61983

Indicators of Compromise

• Unexpected router crashes or reboots, particularly segmentation faults in tmpserver processes
• Abnormal network traffic patterns originating from adjacent network devices targeting the router's management interface
• Unusual process behavior or memory consumption on the affected TP-Link device
• Authentication logs showing repeated access followed by service instability

Detection Strategies

• Monitor network traffic for anomalous packets with excessive empty or zero-length fields targeting TP-Link router services
• Implement intrusion detection rules to identify malformed packets characteristic of buffer overflow attempts
• Deploy network segmentation to limit adjacent network attack surface
• Enable verbose logging on the router to capture crash dumps and error conditions

Monitoring Recommendations

• Configure alerting for router service interruptions or unexpected reboots
• Monitor for authentication attempts from unexpected adjacent network sources
• Implement SIEM rules to correlate authentication events with subsequent device instability
• Track firmware versions across deployed TP-Link devices to identify vulnerable installations

How to Mitigate CVE-2025-61983

Immediate Actions Required

• Update TP-Link Archer AX53 v1.0 firmware to a version newer than 1.3.1 Build 20241120 when available
• Restrict adjacent network access to trusted devices only
• Implement network segmentation to isolate the router from potentially compromised adjacent devices
• Limit administrative access to the router from untrusted network segments

Patch Information

TP-Link has acknowledged this vulnerability. Users should monitor the TP-Link Archer AX53 Firmware Download page for updated firmware releases that address this heap overflow vulnerability. Additional guidance may be available on the TP-Link FAQ Support Page. Technical details about this vulnerability class may also be found via Talos Intelligence Vulnerability Reports.

Workarounds

• Restrict network access to only trusted authenticated users until a patch is available
• Implement firewall rules to filter malformed packets before they reach the router
• Disable unnecessary services on the router to reduce attack surface
• Consider temporarily replacing the affected device with an alternative until patched firmware is released
• Enable MAC address filtering to limit which devices can communicate with the router

# Network isolation recommendation
# Segment the vulnerable router to a dedicated VLAN
# Example: Create VLAN 100 for management traffic only
vlan 100
  name MGMT_ISOLATED
  
# Restrict access to router management interface
interface vlan100
  ip access-group RESTRICT_ARCHER_ACCESS in