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CVE-2021-35033

HIGH

7.8

CVSS Score

Published: November 23, 2021 at 09:20 PM UTC

Updated: June 17, 2026 at 03:57 AM UTC

12 products affected across 1 vendorNBG6818 FirmwareWSQ60 FirmwareWSQ20 Firmware

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Severity

HIGH7.8

Exploit prediction

EPSS 0.4%

Description

A vulnerability in specific versions of Zyxel NBG6818, NBG7815, WSQ20, WSQ50, WSQ60, and WSR30 firmware with pre-configured password management could allow an attacker to obtain root access of the device, if the local attacker dismantles the device and uses a USB-to-UART cable to connect the device, or if the remote assistance feature had been enabled by an authenticated user.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

NBG6818 Firmware · Zyxel

95%

v ≤ 1.00v < 1.00(absc.5)c0

Affected range stops below 1.00(absc.5)c0, so it looks safe — our inference, not a vendor statement

zyxel-nbg6818 (same device)

NBG7815 Firmware · Zyxel

95%

v ≤ 1.00v < 1.00(absk.7)c0

Affected range stops below 1.00(absk.7)c0, so it looks safe — our inference, not a vendor statement

zyxel-nbg7815 (same device)

WSQ20 Firmware · Zyxel

95%

v ≤ 1.00v < 1.00(abof.11)c0

Affected range stops below 1.00(abof.11)c0, so it looks safe — our inference, not a vendor statement

zyxel-wsq20 (same device)

WSQ50 Firmware · Zyxel

95%

v ≤ 2.20v < 2.20(abkj.7)c0

Affected range stops below 2.20(abkj.7)c0, so it looks safe — our inference, not a vendor statement

zyxel-wsq50 (same device)

WSQ60 Firmware · Zyxel

95%

v ≤ 2.20v < 2.20(abnd.8)c0

Affected range stops below 2.20(abnd.8)c0, so it looks safe — our inference, not a vendor statement

zyxel-wsq60 (same device)

WSR30 Firmware · Zyxel

95%

v ≤ 1.00v < 1.00(abmy.12)c0

Affected range stops below 1.00(abmy.12)c0, so it looks safe — our inference, not a vendor statement

zyxel-wsr30 (same device)

Nbg6818 · Zyxeldevice

80%

All versions

Nbg7815 · Zyxeldevice

80%

All versions

Wsq20 · Zyxeldevice

80%

All versions

Wsq50 · Zyxeldevice

80%

All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://www.zyxel.com/support/Zyxel_security_advisory_for_pre-configured_password_management_vulnerability_of_home_routers_and_WiFi_systems.shtml

References (2)

x_refsource_MISCExploitThird Party Advisory

Source: [email protected]

https://www.tenable.com/security/research/tra-2022-06

x_refsource_CONFIRMVendor Advisory

Source: [email protected]

https://www.zyxel.com/support/Zyxel_security_advisory_for_pre-configured_password_management_vulnerability_of_home_routers_and_WiFi_systems.shtml

CVSS

7.8HIGHZyxel

Attack Vector: LOCAL
Complexity: LOW
Privileges: NONE
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-260CWE-287

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