EUVD-2025-21255
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
4Description
A vulnerability was found in Tenda FH1202 1.2.0.14(408). It has been rated as critical. This issue affects the function fromAdvSetWan of the file /goform/AdvSetWan. The manipulation of the argument PPPOEPassword leads to stack-based buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.
Analysis
A critical stack-based buffer overflow vulnerability exists in Tenda FH1202 firmware version 1.2.0.14(408) affecting the /goform/AdvSetWan endpoint. An authenticated remote attacker can overflow the PPPOEPassword parameter to achieve arbitrary code execution with full system privileges (confidentiality, integrity, and availability compromise). Public exploit code is available and the vulnerability meets criteria for active exploitation risk.
Technical Context
The vulnerability resides in the fromAdvSetWan function within Tenda FH1202 router firmware, which processes WAN configuration parameters via HTTP POST requests to /goform/AdvSetWan. The PPPOEPassword parameter lacks proper input validation and length checking before being copied into a stack-allocated buffer, violating CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). Tenda FH1202 is a wireless router device running proprietary firmware. The affected CPE context is likely: cpe:2.3:o:tenda:fh1202_firmware:1.2.0.14\(408\):*:*:*:*:*:*:*. Stack-based buffer overflows in embedded router firmware typically allow attackers to overwrite return addresses and execute shellcode within the kernel or privileged userland process context.
Affected Products
[{'vendor': 'Tenda', 'product': 'FH1202', 'affected_versions': ['1.2.0.14(408)'], 'device_type': 'Wireless Router', 'cpe': 'cpe:2.3:o:tenda:fh1202_firmware:1.2.0.14\\(408\\):*:*:*:*:*:*:*', 'notes': 'Older wireless router model; unclear if newer firmware versions patched. Verify 1.2.0.15+ availability.'}]
Remediation
[{'type': 'Patch', 'action': "Upgrade Tenda FH1202 firmware to version 1.2.0.15 or later (if available). Check Tenda's official support page for FH1202 security updates at https://www.tenda.com.cn/download/", 'priority': 'IMMEDIATE'}, {'type': 'Workaround - Network Segmentation', 'action': "Restrict administrative access to the router's web interface (port 80/443) to trusted internal networks only. Block external WAN access via firewall rules.", 'priority': 'HIGH'}, {'type': 'Workaround - Credential Management', 'action': 'Change default admin credentials to strong, unique passwords to reduce likelihood of authenticated exploit. However, this is NOT a complete mitigation as authenticated users on the network could still exploit.', 'priority': 'MEDIUM'}, {'type': 'Mitigation - Network Monitoring', 'action': 'Monitor for suspicious HTTP POST requests to /goform/AdvSetWan with unusually long PPPOEPassword values or binary payloads. Alert on firmware crashes/reboots.', 'priority': 'MEDIUM'}, {'type': 'Device Replacement', 'action': 'If patch unavailable, consider replacing FH1202 with newer router models from reputable vendors with active security support.', 'priority': 'HIGH'}]
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External POC / Exploit Code
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