Cyber Resilience

CVE-2021-35029

Critical

Published: 02 July 2021

Published
02 July 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0020 41.4th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-35029 is a critical-severity Improper Authentication (CWE-287) vulnerability in Zyxel Usg1900 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, ranked at the 41.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

on an affected device.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

zyxel
usg1900 firmware
4.35 — 4.64
zyxel
usg1100 firmware
4.35 — 4.64
zyxel
usg310 firmware
4.35 — 4.64
zyxel
usg210 firmware
4.35 — 4.64
zyxel
usg110 firmware
4.35 — 4.64
zyxel
usg40 firmware
4.35 — 4.64
zyxel
usg40w firmware
4.35 — 4.64
zyxel
usg60 firmware
4.35 — 4.64
zyxel
usg60w firmware
4.35 — 4.64
zyxel
usg300 firmware
4.35 — 4.64
+27 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-287

Detects unauthorized successful logons resulting from improper authentication implementations.

addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

addresses: CWE-287

Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.

addresses: CWE-287

Session content review can reveal authentication bypasses or failures in session establishment.

addresses: CWE-287

Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.

addresses: CWE-287

Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.

References