Buffer Overflow Vulnerability in Zyxel VMG4005-B50B Firmware
CVE-2026-3870

6.5MEDIUM

Key Information:

Vendor

Zyxel
Status
Vmg4005-b50b Firmware
Vendor
CVE Published:
2 June 2026

What is CVE-2026-3870?

A buffer overflow flaw exists in the UPnP AddPortMapping() command within the Zyxel VMG4005-B50B firmware. This vulnerability may be exploited by an adjacent attacker to create a temporary denial-of-service condition, disrupting the UPnP functionality of the affected device. Users are urged to apply the latest firmware updates to mitigate this risk.

Affected Version(s)

VMG4005-B50B firmware <= 5.13(ABRL.5.4)C0

References

https://www.zyxel.com/global/en/support/security-advisori...
vendor-advisory

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Adjacent Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.