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CVE-2022-0734· NVD / CVE Program· CNA Zyxel

A cross-site scripting vulnerability was identified in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.35 through 4.70, USG F

A cross-site scripting vulnerability was identified in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.35 through 4.70, USG FLEX series firmware versions 4.50 through 5.20, ATP series firmware versions 4.35 through 5.20, and VPN series firmware versions 4.35 through 5.20, that could allow an attacker to obtain some information stored in the user's browser, such as cookies or session tokens, via a malicious script.

MediumCVSS 6.1 · v3.1—No exploit No fix recorded
Published
May 23, 2022
Updated
Jun 17, 2026
EPSS
9.4% · 95th percentile
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Action score

27

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
3 / 30 · 9.4%

CNA vs NVD score

NVD
6.1
CNA · Zyxel
5.8
0.3 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

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Affected systems

VendorProduct
zyxelusg 60
zyxelvpn100 firmware
zyxelvpn100
zyxelvpn1000 firmware
zyxelvpn1000
zyxelvpn300 firmware
zyxelvpn300
zyxelvpn50 firmware
zyxelvpn50
zyxelatp100 firmware
zyxelatp100
zyxelatp100w firmware

and 52 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zyxel atp100 firmware4.35 and later · up to 5.20 inclusive
  • zyxel atp100w firmware4.35 and later · up to 5.20 inclusive
  • zyxel atp200 firmware4.35 and later · up to 5.20 inclusive
  • zyxel atp500 firmware4.35 and later · up to 5.20 inclusive
  • zyxel atp700 firmware4.35 and later · up to 5.20 inclusive
  • zyxel atp800 firmware4.35 and later · up to 5.20 inclusive
  • zyxel usg 110 firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 1100 firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 1900 firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 20w firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 20w-vpn firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 2200-vpn firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 310 firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 40 firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 40w firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 60 firmware4.35 and later · up to 4.70 inclusive
  • zyxel usg 60w firmware4.35 and later · up to 4.70 inclusive
  • 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

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

    • 4.35 through 5.20affected

  • Zyxel USG FLEX series firmware

    • 4.50 through 5.20affected

  • Zyxel USG/ZyWALL series firmware

    • 4.35 through 4.70affected

  • Zyxel VPN series firmware

    • 4.35 through 5.20affected

Same product

zyxel: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-26531Multiple improper input validation flaws were identified in some CLI commands of Zyxel USG/ZyWALL series firmware versions 4.09 through 4.71
    33Monitor
  • CVE-2022-26532A argument injection vulnerability in the 'packet-trace' CLI command of Zyxel USG/ZyWALL series firmware versions 4.09 through 4.71, USG FLE
    32Monitor
  • CVE-2022-0910A downgrade from two-factor authentication to one-factor authentication vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware
    26Monitor

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

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

EPSS, last 120 days

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 researchers

Finders, 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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

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.

All records