What is CVE-2025-50402?

CVE-2025-50402 is a critical-severity vulnerability in Fastcom Fac1200r, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2025-11-26.

How severe is CVE-2025-50402?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Fastcom Fac1200r

CVE-2025-50402

FAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter string fac_password.

Vulnerability class: Buffer Overflow

Published 2025-11-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (34.2th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Fastcom Fac1200r
Fastcom Fac1200r Firmware — versions f400_fac1200r_q

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

github.com/sezangel/IOT-vul/tree/main/FAST/FAC1200R/2 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2025-50402?: CVE-2025-50402 is a critical-severity vulnerability in Fastcom Fac1200r, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2025-11-26.
How severe is CVE-2025-50402?: Critical severity. CVSS v3 base score is 9.8 out of 10.