What is CVE-2025-7673?

CVE-2025-7673 is a critical-severity vulnerability in Zyxel Emg3525-t50b, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2025-07-16.

How severe is CVE-2025-7673?

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

Buffer overflow in Zyxel Emg3525-t50b

CVE-2025-7673

A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially…

Vulnerability class: Buffer Overflow

EPSS: 0.005 (41.6th percentile) — read the EPSS interpretation.

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.

Affected products

Weakness classification (CWE)

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

References

security@zyxel.com.tw (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2025-7673?: CVE-2025-7673 is a critical-severity vulnerability in Zyxel Emg3525-t50b, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2025-07-16.
How severe is CVE-2025-7673?: Critical severity. CVSS v3 base score is 9.8 out of 10.