CVE-2021-43698Public exploitNetwork attack vector

Browser script execution via unencoded query reflection

Published Nov 29, 2021 · Updated Aug 4, 2024

Cross-site scripting in phpWhois example.php allows remote attackers to run script in a user’s browser through a crafted query parameter. The page copies $_GET['query'] into the {query} placeholder and returns the assembled HTML through exit() without output encoding. Exploitation requires a user to open an attacker-crafted request; injected script runs in that user’s browser context and can read or alter page-accessible data.

CVSS severity6.1
Medium
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in phpWhois example.php allows remote attackers to run script in a user’s browser through a crafted query parameter. The page copies $_GET['query'] into the {query} placeholder and returns the assembled HTML through exit() without output encoding. Exploitation requires a user to open an attacker-crafted request; injected script runs in that user’s browser context and can read or alter page-accessible data.

The record

CVE
CVE-2021-43698
Published
Nov 29, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

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

Technologies

Your stack

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Your stack

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