Auth bypass in Zyxel Nbg2105

CVE-2021-3297

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

Vulnerability class: Broken Authentication

EPSS: 0.205 (97.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-3297?
CVE-2021-3297 is a high-severity vulnerability in Zyxel Nbg2105, classified under Improper Authentication. CVSS score: 7.8/10. Published 2021-01-26.
How severe is CVE-2021-3297?
High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2021-3297 known to be exploited?
21 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.