What is CVE-2021-35027?

CVE-2021-35027 is a high-severity vulnerability in Zyxel Zywall Vpn2s, classified under CWE-27. CVSS score: 7.5/10. Published 2021-09-29.

How severe is CVE-2021-35027?

High severity. CVSS v3 base score is 7.5 out of 10.

Path Traversal in Zyxel Zywall Vpn2s

CVE-2021-35027

A directory traversal vulnerability in the web server of the Zyxel VPN2S firmware version 1.12 could allow a remote attacker to gain access to sensitive information.

Published 2021-09-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.020 (80.9th percentile), scored 2026-10-19.

Low probability of exploitation in the next 30 days, but still tracked. 81st percentile — 80.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.020 · newest: 0.020 · change: 0.000

Affected products

Zyxel Zywall Vpn2s
Zyxel Zywall Vpn2s Firmware — versions 1.12(ABLN.0)C0
Zyxel Zywall Vpn2s Firmware — versions 1.12(abln.0)c0, 1.12\(abln.0\)c0

Weakness classification (CWE)

References

www.zyxel.com/support/Zyxel_security_advisory_for_directory_traversal_and_comma… (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2021-35027?: CVE-2021-35027 is a high-severity vulnerability in Zyxel Zywall Vpn2s, classified under CWE-27. CVSS score: 7.5/10. Published 2021-09-29.
How severe is CVE-2021-35027?: High severity. CVSS v3 base score is 7.5 out of 10.