CVE-2025-70646
Published: 21 January 2026
Summary
CVE-2025-70646 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Tenda Ax1803 Firmware. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 31.3th 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 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2025-70646 is a stack overflow vulnerability (CWE-121) in the security parameter of the sub_72290 function within Tenda AX1803 firmware version v1.0.0.1. This flaw enables attackers to trigger a Denial of Service (DoS) condition through a specially crafted network request. The vulnerability was publicly disclosed on January 21, 2026, and carries a CVSS v3.1 base score of 7.5, reflecting its high severity due to the potential for remote disruption without authentication.
The attack scenario is straightforward and highly accessible: unauthenticated attackers with network access to the affected device (AV:N/AC:L/PR:N/UI:N) can send a malicious request to the vulnerable function, causing a stack overflow that crashes the device and disrupts service availability (A:H). No user interaction or privileges are required, making it suitable for remote exploitation by any adversary on the same network or exposed to the internet. Successful exploitation results solely in DoS, with no impact on confidentiality or integrity (C:N/I:N).
Mitigation details and further technical analysis are provided in the referenced advisory at https://github.com/0-fool/VulnbyCola/blob/main/Tenda/AX-1803/5/1.md. Security practitioners should consult this source for reproduction steps, patch information if available, and recommended remediation actions, such as firmware updates or network segmentation.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3656
Vulnerability details
Tenda AX1803 v1.0.0.1 was discovered to contain a stack overflow in the security parameter of the sub_72290 function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted request.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote unauthenticated stack overflow in public-facing router firmware directly enables T1190 exploitation and T1499.004 DoS via application/system exploitation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforces validation of the security parameter input in sub_72290 to directly prevent stack overflow from crafted requests.
Provides timely remediation of the specific stack overflow flaw through firmware patching or updates.
Implements mechanisms to protect against the DoS caused by stack overflow crashes from unauthenticated remote requests.