CVE-2026-30814: TP-Link Archer AX53 Buffer Overflow Flaw

CVE-2026-30814 Overview

A stack-based buffer overflow vulnerability has been identified in the tmpServer module of TP-Link Archer AX53 v1.0 wireless routers. This vulnerability allows an authenticated attacker with adjacent network access to trigger a segmentation fault and potentially execute arbitrary code by supplying a specially crafted configuration file to the affected module.

Successful exploitation of this vulnerability may result in device crashes, arbitrary code execution on the router, modification of device state, exposure of sensitive network configuration data, or further compromise of device integrity. Given the router's position as a network gateway, exploitation could provide attackers with a foothold for lateral movement within the network.

Critical Impact

Authenticated adjacent attackers can achieve arbitrary code execution on TP-Link Archer AX53 routers, potentially compromising network integrity and enabling further attacks on connected devices.

Affected Products

• TP-Link Archer AX53 v1.0 firmware versions prior to 1.7.1 Build 20260213

Discovery Timeline

• 2026-04-08 - CVE-2026-30814 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2026-30814

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption vulnerability that occurs when a program writes data beyond the boundaries of a pre-allocated fixed-size buffer on the stack. In the context of the TP-Link Archer AX53, the vulnerable code resides within the tmpServer module, which processes configuration files without properly validating input length.

The exploitation requires an authenticated user on the adjacent network to submit a malicious configuration file. When the tmpServer module processes this oversized input, it overwrites adjacent stack memory, including return addresses and saved registers. This memory corruption can lead to control flow hijacking, allowing the attacker to redirect execution to attacker-controlled code.

Root Cause

The root cause of this vulnerability is insufficient bounds checking in the tmpServer module when handling configuration file data. The affected code allocates a fixed-size stack buffer for configuration data but fails to validate that incoming data fits within the allocated space. When configuration data exceeds the buffer size, the excess bytes overwrite critical stack structures, including the return address used to resume normal program execution after function completion.

Attack Vector

The attack requires adjacent network access, meaning the attacker must be on the same local network segment as the target router. Additionally, the attacker must possess valid authentication credentials to interact with the vulnerable tmpServer module. The attack is executed by:

1. Authenticating to the router's management interface
2. Crafting a configuration file with an oversized payload designed to overflow the stack buffer
3. Submitting the malicious configuration file to the tmpServer module
4. Triggering code execution through carefully placed shellcode or ROP chains that overwrite the return address

The vulnerability does not require user interaction beyond the initial authentication. Due to the adjacent network requirement, remote exploitation over the internet is not directly possible without first compromising the local network.

Detection Methods for CVE-2026-30814

Indicators of Compromise

• Unexpected router reboots or service crashes involving the tmpServer process
• Unusual configuration file uploads or modifications via the router's management interface
• Abnormal network traffic patterns originating from the router itself
• Unauthorized changes to router settings or firmware

Detection Strategies

• Monitor router logs for segmentation faults or crashes in the tmpServer module
• Implement network monitoring to detect unusual management interface activity from unauthorized hosts
• Deploy intrusion detection rules to identify oversized or malformed configuration file submissions
• Audit authentication logs for unexpected or repeated login attempts from adjacent network devices

Monitoring Recommendations

• Enable verbose logging on the TP-Link Archer AX53 if supported by the firmware
• Deploy network-based monitoring solutions to track management interface access patterns
• Implement alerting for any router service restarts or unexpected device reboots
• Review connected device lists regularly for unauthorized network access

How to Mitigate CVE-2026-30814

Immediate Actions Required

• Update TP-Link Archer AX53 v1.0 firmware to version 1.7.1 Build 20260213 or later immediately
• Restrict administrative access to trusted devices only using MAC filtering or access control lists
• Change default administrative credentials if not already done
• Disable remote management features if not required
• Audit network for any unauthorized devices that could have adjacent network access

Patch Information

TP-Link has released firmware version 1.7.1 Build 20260213 which addresses this stack-based buffer overflow vulnerability. The patched firmware is available through the TP-Link Archer AX53 Firmware Download page. Organizations should prioritize firmware updates for all affected devices.

Additional information about the vulnerability and mitigation guidance can be found in the TP-Link FAQ #5055 and Talos Intelligence Vulnerability Reports.

Workarounds

• Implement network segmentation to isolate IoT devices and routers from general user networks
• Use a separate VLAN for management traffic to limit adjacent network exposure
• Enable strong authentication mechanisms and complex passwords for router administration
• Consider deploying a firewall or network monitoring solution upstream of the affected device
• Disable unnecessary services on the router to reduce the attack surface

# Configuration example - Network segmentation for router management
# Create a dedicated management VLAN to restrict adjacent network access
# These commands are conceptual - actual syntax varies by network equipment

# On upstream switch, create management VLAN
vlan 100
  name MGMT_VLAN

# Assign router management port to VLAN 100
interface ethernet1/1
  switchport mode access
  switchport access vlan 100

# Restrict management VLAN access via ACL
access-list MGMT_ACCESS permit ip 192.168.100.0/24 any
access-list MGMT_ACCESS deny ip any any