LB-LINK BL-LTE300_DA4 /goform/set_serial_cfg command injection

Summaryinfo

A vulnerability marked as critical has been reported in LB-LINK BL-AC2100_AZ3, BL-WR4000, BL-WR9000_AE4, BL-AC1900_AZ2, BL-X26_AC8 and BL-LTE300_DA4. Affected by this vulnerability is an unknown functionality of the file /goform/set_serial_cfg. The manipulation leads to command injection. This vulnerability is traded as CVE-2025-57685. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in LB-LINK BL-AC2100_AZ3, BL-WR4000, BL-WR9000_AE4, BL-AC1900_AZ2, BL-X26_AC8 and BL-LTE300_DA4. It has been rated as critical. This issue affects an unknown code of the file /goform/set_serial_cfg. The manipulation with an unknown input leads to a command injection vulnerability. Using CWE to declare the problem leads to CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

The LB-Link routers, including the BL-AC2100_AZ3 V1.0.4, BL-WR4000 v2.5.0, BL-WR9000_AE4 v2.4.9, BL-AC1900_AZ2 v1.0.2, BL-X26_AC8 v1.2.8, and BL-LTE300_DA4 V1.2.3 models, are vulnerable to unauthorized command injection. Attackers can exploit this vulnerability by accessing the /goform/set_serial_cfg interface to gain the highest level of device privileges without authorization, enabling them to remotely execute malicious commands.

The identification of this vulnerability is CVE-2025-57685 since 08/17/2025. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/29/2025). The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-30735). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• LB-LINK

Name

• BL-AC1900_AZ2
• BL-AC2100_AZ3
• BL-LTE300_DA4
• BL-WR4000
• BL-WR9000_AE4
• BL-X26_AC8

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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