CVE-2026-3870 — MEDIUM (6.5)

Vulnerability Description

A buffer overflow vulnerability in the UPnP AddPortMapping() command in Zyxel VMG4005-B50B firmware versions through 5.13(ABRL.5.4)C0 could allow an adjacent attacker to trigger a temporary denial-of-service (DoS) condition affecting the UPnP function of the affected device.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

ADJACENT_NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Related Weaknesses (CWE)

CWE-120

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advis

FAQ

What is CVE-2026-3870?

CVE-2026-3870 is a vulnerability with a CVSS score of 6.5 (MEDIUM). A buffer overflow vulnerability in the UPnP AddPortMapping() command in Zyxel VMG4005-B50B firmware versions through 5.13(ABRL.5.4)C0 could allow an adjacent attacker to trigger a temporary denial-of-...

How severe is CVE-2026-3870?

CVE-2026-3870 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-3870?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.