CVE-2022-0734Known exploitationNetwork attack vector

Browser data theft via CGI cross-site scripting

Published May 24, 2022 · Updated Aug 2, 2024

Cross-site scripting in Zyxel USG, FLEX, ATP, and VPN firewall firmware allows remote attackers to steal browser cookies or session tokens. Zyxel identifies the vulnerable locus only as the CGI program and does not disclose the endpoint, parameter, or unsafe output operation. USG/ZyWALL 4.35 through 4.70, USG FLEX 4.50 through 5.20, and ATP and VPN 4.35 through 5.20 are affected; exploitation requires malicious script execution in a user's browser.

CVSS severity5.8
Medium
EPSS probability9.19%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Zyxel USG, FLEX, ATP, and VPN firewall firmware allows remote attackers to steal browser cookies or session tokens. Zyxel identifies the vulnerable locus only as the CGI program and does not disclose the endpoint, parameter, or unsafe output operation. USG/ZyWALL 4.35 through 4.70, USG FLEX 4.50 through 5.20, and ATP and VPN 4.35 through 5.20 are affected; exploitation requires malicious script execution in a user's browser.

The record

CVE
CVE-2022-0734
Published
May 24, 2022
Updated
Aug 2, 2024
Vendor
Zyxel Networks
Product
Zyxel ATP Series Firmware
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.35 through 5.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zyxel Networks · Zyxel ATP Series Firmwareversion=4.35 through 5.20
Zyxel Networks · Zyxel ZyWALL/USG Series Firmwareversion=4.35 through 4.70
Zyxel Networks · Zyxel VPN Series Firmwareversion=4.35 through 5.20
Zyxel Networks · Zyxel USG FLEX Series Firmwareversion=4.50 through 5.20

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.8Zyxel CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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