How severe is CVE-2022-0342?

CVE-2022-0342 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2022-0342 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 85% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-0342?

CVE-2022-0342 primarily affects Zyxel Usg40 Firmware. In total, 25 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2022-0342?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2022-0342 published?

CVE-2022-0342 was published on 2022-03-28 and last updated on 2026-06-17.

CVE-2022-0342

CVE-2022-0342 is a critical-severity vulnerability in Zyxel Usg40 Firmware with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 85% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 85% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Zyxel Usg40 Firmware
Published: 2022-03-28
Last modified: 2026-06-17

Description

An authentication bypass vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.20 through 4.70, USG FLEX series firmware versions 4.50 through 5.20, ATP series firmware versions 4.32 through 5.20, VPN series firmware versions 4.30 through 5.20, and NSG series firmware versions V1.20 through V1.33 Patch 4, which could allow an attacker to bypass the web authentication and obtain administrative access of the device.

Frequently asked questions

What is CVE-2022-0342?: An authentication bypass vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.20 through 4.70, USG FLEX series firmware versions 4.50 through 5.20, ATP series firmware versions 4.32 through 5.20, VPN series firmware versions 4.30 through 5.20, and NSG series firmware versions V1.20 through V1.33 Patch 4, which could allow an attacker to bypass the web authentication and obtain administrative access of the device.
How severe is CVE-2022-0342?: CVE-2022-0342 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2022-0342 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 85% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-0342?: CVE-2022-0342 primarily affects Zyxel Usg40 Firmware. In total, 25 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-0342?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2022-0342 published?: CVE-2022-0342 was published on 2022-03-28 and last updated on 2026-06-17.

References

https://www.zyxel.com/support/Zyxel-security-advisory-for-authentication-bypass-vulnerability-of-firewalls.shtml

Affected products (25)

cpe:2.3:o:zyxel:usg40_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg40w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg60_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg60w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:zywall_110_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:zywall_310_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:zywall_1100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn50_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn1000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:p4:*:*:*:*:*:*

More vulnerabilities in Zyxel Usg40 Firmware

CVE-2021-35029 — Critical (CVSS 9.8): An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware…
CVE-2020-29583 — Critical (CVSS 9.8): Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The…
CVE-2020-9054 — Critical (CVSS 9.8): Multiple ZyXEL network-attached storage (NAS) devices running firmware version 5.21 contain a pre-authentication…
CVE-2022-30526 — High (CVSS 7.8): A privilege escalation vulnerability was identified in the CLI command of Zyxel USG FLEX 100(W) firmware versions 4.50…
CVE-2022-38547 — High (CVSS 7.2): A post-authentication command injection vulnerability in the CLI command of Zyxel ZyWALL/USG series firmware versions…
CVE-2022-2030 — Medium (CVSS 6.5): A directory traversal vulnerability caused by specific character sequences within an improperly sanitized URL was…

All CVEs affecting Zyxel Usg40 Firmware →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →