CVE-2021-3297: Zyxel NBG2105 Firmware

High severity, CVSS 7.8. EPSS: 20.5% chance of exploitation in the next 30 days.

On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.

Affected products

• Zyxel NBG2105 Firmware: version v1.00(aagu.2)c0 only

Published 2021-01-26. Last modified 2026-06-17.