CVE-2025-50402
Memory Safety in Fastcom Fac1200R Firmware f400_fac1200r_q
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-50402 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Fastcom Fac1200R Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Server (T1584.004); ranked at the 35th 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 map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2025-50402 is a buffer overflow vulnerability (CWE-120) affecting the FAST FAC1200R F400_FAC1200R_Q firmware or component. The issue resides in the function sub_80435780, which can be triggered via a specially crafted value in the fac_password parameter. Published on 2025-11-26 with 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), it represents a critical remote code execution risk in this IoT device firmware.
An unauthenticated attacker with network access can exploit this vulnerability by sending a malicious fac_password string to the affected component, leading to a buffer overflow. Successful exploitation allows arbitrary code execution with high impact on confidentiality, integrity, and availability, potentially resulting in full device compromise, such as router takeover for further network pivoting or data exfiltration.
References point to a GitHub repository (https://github.com/sezangel/IOT-vul/tree/main/FAST/FAC1200R/2) containing vulnerability details or proof-of-concept code for the FAST FAC1200R, but no official advisories or patches are detailed in available information. Security practitioners should isolate affected devices and monitor for firmware updates from the vendor.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-199731
Vulnerability Data
FAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter string fac_password.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
—
V5.2.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and analysis can find missing size checks before deployment.
Input validation directly enforces size checks before buffer copies.
Engineering principles require bounds checking and safe buffer handling in design.
Memory protection limits the impact of an overflow once it occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.
Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.
Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.
Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.