An authentication bypass vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.20 through 4.70, USG FLEX series fi
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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Mar 28, 2022
- Updated
- Jun 17, 2026
- EPSS
- 95.1% · 100th percentile
- CWE
- CWE-287
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
68
This week
Don’t wait for the next maintenance window.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 29 / 30 · 95.1%
CNA vs NVD score
- NVD
- 9.8
- CNA · Zyxel
- 9.8
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| zyxel | usg40 firmware | cpe:2.3:o:zyxel:usg40_firmware |
| zyxel | usg40 | cpe:2.3:h:zyxel:usg40 |
| zyxel | usg40w firmware | cpe:2.3:o:zyxel:usg40w_firmware |
| zyxel | usg40w | cpe:2.3:h:zyxel:usg40w |
| zyxel | usg60 firmware | cpe:2.3:o:zyxel:usg60_firmware |
| zyxel | usg60 | cpe:2.3:h:zyxel:usg60 |
| zyxel | usg60w firmware | cpe:2.3:o:zyxel:usg60w_firmware |
| zyxel | usg60w | cpe:2.3:h:zyxel:usg60w |
| zyxel | zywall 110 firmware | cpe:2.3:o:zyxel:zywall_110_firmware |
| zyxel | zywall 110 | cpe:2.3:h:zyxel:zywall_110 |
| zyxel | zywall 310 firmware | cpe:2.3:o:zyxel:zywall_310_firmware |
| zyxel | zywall 310 | cpe:2.3:h:zyxel:zywall_310 |
and 34 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- zyxel atp100 firmware4.32 and later · up to 5.20 inclusive
- zyxel atp100w firmware4.32 and later · up to 5.20 inclusive
- zyxel atp200 firmware4.32 and later · up to 5.20 inclusive
- zyxel atp500 firmware4.32 and later · up to 5.20 inclusive
- zyxel atp700 firmware4.32 and later · up to 5.20 inclusive
- zyxel atp800 firmware4.32 and later · up to 5.20 inclusive
- zyxel nsg300 firmware1.20 and later · before 1.33
- zyxel nsg300 firmware1.33
- zyxel usg flex 100 firmware4.50 and later · up to 5.20 inclusive
- zyxel usg flex 100w firmware4.50 and later · up to 5.20 inclusive
- zyxel usg flex 200 firmware4.50 and later · up to 5.20 inclusive
- zyxel usg flex 500 firmware4.50 and later · up to 5.20 inclusive
- zyxel usg flex 700 firmware4.50 and later · up to 5.20 inclusive
- zyxel usg40 firmware4.20 and later · before 4.71
- zyxel usg40w firmware4.20 and later · before 4.71
- zyxel usg60 firmware4.20 and later · before 4.71
- zyxel usg60w firmware4.20 and later · before 4.71
- zyxel vpn100 firmware4.30 and later · before 5.21
- zyxel vpn1000 firmware4.30 and later · before 5.21
- zyxel vpn300 firmware4.30 and later · before 5.21
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Zyxel). Independent of NVD's CPE analysis and usually ahead of it.
Zyxel ATP series firmware
- 4.32 through 5.20affected
Zyxel NSG series firmware
- 1.20 through 1.33 Patch 4affected
Zyxel USG FLEX series firmware
- 4.50 through 5.20affected
Zyxel USG/ZyWALL series firmware
- 4.20 through 4.70affected
Zyxel VPN series firmware
- 4.30 through 5.20affected
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Nuclei detection template ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Nuclei detection template | Nuclei template CVE-2022-0342 | — |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-287 · Improper AuthenticationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.
The bug in code
The whole CWE-287 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);Fixed
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Authentication AbuseCAPEC-114Medium
- Authentication BypassCAPEC-115Medium
- Identity SpoofingCAPEC-151likelihood: Medium · Medium
- Fake the Source of DataCAPEC-194Medium
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-57likelihood: Medium · Very High
- Session HijackingCAPEC-593likelihood: High · Very High
- Token ImpersonationCAPEC-633Medium
ATT&CK techniques
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.