Is CVE-2021-35029 actively exploited?

No active exploitation of CVE-2021-35029 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-35029 be exploited remotely?

Yes. CVE-2021-35029 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-35029?

CVE-2021-35029 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-35029

CWE-287Published: July 2, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.

NVD Source

Technical Analysis

CVE-2021-35029 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-287): Authentication bypass vulnerabilities allow attackers to access protected resources without valid credentials.