CVE-2025-12239
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-27

Last updated on: 2025-10-27

Assigner: VulDB

Description
A weakness has been identified in TOTOLINK A3300R 17.0.0cu.557_B20221024. The impacted element is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. Executing manipulation can lead to buffer overflow. The attack may be performed from remote. The exploit has been made available to the public and could be exploited.
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Meta Information
Published
2025-10-27
Last Modified
2025-10-27
Generated
2026-06-16
AI Q&A
2025-10-27
EPSS Evaluated
2026-06-15
NVD
CVE-2025-12239
EUVD
EUVD-2025-36098
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
totolink a3300r_firmware 17.0.0cu.557_b20221024
totolink a3300r *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
CWE-120 The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
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Executive Summary

CVE-2025-12239 is a critical buffer overflow vulnerability in the TOTOLINK A3300R router firmware version 17.0.0cu.557_B20221024. The flaw exists in the setDdnsCfg function within the /cgi-bin/cstecgi.cgi file, specifically in handling the 'provider' POST parameter. The input is copied to an output buffer without checking if the input size exceeds the buffer size, causing a buffer overflow (CWE-120). This can be exploited remotely to compromise the device. [1, 2]

Impact Analysis

This vulnerability can allow a remote attacker to execute arbitrary code or cause a denial of service on the affected TOTOLINK A3300R router. Exploiting the buffer overflow can compromise the confidentiality, integrity, and availability of the device, potentially leading to full device takeover or disruption of network services. [1, 2]

Detection Guidance

This vulnerability can be detected by monitoring or testing the /cgi-bin/cstecgi.cgi endpoint, specifically the setDdnsCfg function that accepts a POST parameter named "provider". Sending an excessively long "provider" parameter in a POST request to this endpoint may trigger the buffer overflow. You can use tools like curl to test this by sending a crafted POST request with a long "provider" value, for example: curl -X POST http://<router-ip>/cgi-bin/cstecgi.cgi -d "action=setDdnsCfg&provider=$(python3 -c 'print("A"*1000)')". Additionally, network intrusion detection systems (NIDS) can be configured to alert on unusually long POST parameters to this endpoint. However, no specific detection commands or signatures are provided in the resources. [2, 3]

Mitigation Strategies

Immediate mitigation steps include avoiding exposure of the vulnerable TOTOLINK A3300R router's management interface to untrusted networks, especially the /cgi-bin/cstecgi.cgi endpoint. Since no known mitigations or patches are available, it is recommended to replace the affected device with an alternative product. Limiting network access to the device and monitoring for exploit attempts can also help reduce risk. [1]

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