CVE-2025-69766
Published: 21 January 2026
Summary
CVE-2025-69766 is a critical-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Tenda Ax3 Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 47.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2025-69766, published on 2026-01-21, is a stack-based buffer overflow vulnerability in the formGetIptv function of Tenda AX3 firmware version v16.03.12.11. The flaw stems from improper handling of the citytag stack buffer, which can lead to memory corruption and remote code execution. It is classified under CWE-121 and carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Unauthenticated attackers with network access can exploit this vulnerability due to its low attack complexity and lack of required privileges or user interaction. Successful exploitation enables remote code execution on the targeted device, resulting in high-impact compromises to confidentiality, integrity, and availability.
Advisories providing further details on the vulnerability are available at the following references: https://river-brow-763.notion.site/Tenda-AX3-Buffer-Overflow-in-formGetIptv-2c9a595a7aef8043a091e6722b8e255a and https://river-brow-763.notion.site/Tenda-AX3-Buffer-Overflow-in-formGetIptv-2c9a595a7aef8043a091e6722b8e255a?source=copy_link.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3647
Vulnerability details
Tenda AX3 firmware v16.03.12.11 contains a stack-based buffer overflow in the formGetIptv function due to improper handling of the citytag stack buffer, which may result in memory corruption and remote code execution.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Unauthenticated stack-based buffer overflow in router firmware enables remote code execution on a public-facing application.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the improper handling of the citytag input in formGetIptv by enforcing input validation at critical entry points to prevent stack buffer overflows.
Implements memory protection mechanisms like stack canaries and non-executable stacks to mitigate exploitation of stack-based buffer overflows leading to memory corruption.
Mandates identification, reporting, and correction of flaws such as this buffer overflow in Tenda AX3 firmware to prevent remote code execution.