CVE-2022-0342
CriticalExploitedAn 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…
Published Apr 4, 2022 · Updated Aug 2, 2024 · Also known as TR-22-0280
Key Facts
Patch immediately- CVE-2022-0342 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Atp100 Firmware (Zyxel), Atp100w Firmware (Zyxel), Atp200 Firmware (Zyxel) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since Oct 17, 2025. No public exploit code is known.
- EPSS estimates a 95% probability of exploitation in the next 30 days.
- Fixed versions are available, including Atp100 Firmware <=5.20, Atp100w Firmware <=5.20, Atp200 Firmware <=5.20.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
95%
Higher than 99.8% of all scored CVEs
Exploited in the wild
Yes
1 catalog listing
Public exploit code
None known
Get the full CVE-2022-0342 brief as a PDF
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Oct 17, 2025 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
30 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Atp100 FirmwareZyxel | See advisory | 5.20 |
| Atp100w FirmwareZyxel | See advisory | 5.20 |
| Atp200 FirmwareZyxel | See advisory | 5.20 |
| Atp500 FirmwareZyxel | See advisory | 5.20 |
| Atp700 FirmwareZyxel | See advisory | 5.20 |
Patched Releases
Atp100 Firmware
<=5.20
Atp100w Firmware
<=5.20
Atp200 Firmware
<=5.20
Atp500 Firmware
<=5.20
Atp700 Firmware
<=5.20
Atp800 Firmware
<=5.20
Nsg300 Firmware
1.33
Usg Flex 100 Firmware
<=5.20
Usg Flex 100w Firmware
<=5.20
Usg Flex 200 Firmware
<=5.20
Usg Flex 500 Firmware
<=5.20
Usg Flex 700 Firmware
<=5.20
Usg40 Firmware
4.71
Usg40w Firmware
4.71
Usg60 Firmware
4.71
Usg60w Firmware
4.71
Vpn100 Firmware
5.21
Vpn1000 Firmware
5.21
Vpn300 Firmware
5.21
Vpn50 Firmware
5.21
Zywall 110 Firmware
4.71
Zywall 1100 Firmware
4.71
Zywall 310 Firmware
4.71
Timeline
Publicly disclosed
Apr 4, 2022
Last updated
Aug 2, 2024
Added to Industry KEV feed
Oct 17, 2025
Weakness Type
- CWE-287 Improper Authentication
References
- advisoryhttps://securityaffairs.co/wordpress
- advisoryhttps://securityaffairs.co/wordpress/129689/security/zyxel-firewalls-authentication-bypass.html
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2022-0342
- advisoryhttps://www.cybersecurity-review.com/news-april-2022/zyxel-urges-customers-to-patch-critical-firewall-bypass-vulnerability/
- advisoryhttps://www.itsecuritynews.info/zyxel-fixes-a-critical-bug-in-its-business-firewall-and-vpn-devices/
FAQ
Common Questions.
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 V…
Affected: Atp100 Firmware (Zyxel); Atp100w Firmware (Zyxel); Atp200 Firmware (Zyxel), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Oct 17, 2025.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Atp100 Firmware <=5.20, Atp100w Firmware <=5.20, Atp200 Firmware <=5.20.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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