CVE-2021-4169Network attack vector

Reflected XSS via unescaped avatar path identifier

Published Dec 26, 2021 · Updated Aug 3, 2024

Reflected XSS in LiveHelperChat Live Helper Chat 3.90 and earlier allows remote attackers to execute script via a crafted avatar ID. The avatarbuilder route places its path identifier in a single-quoted image source attribute without neutralizing embedded single quotes. No authentication is required, but a user must open the crafted request; injected script runs in that user's browser context and can read or modify accessible page data.

CVSS severity6.1
Medium
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in LiveHelperChat Live Helper Chat 3.90 and earlier allows remote attackers to execute script via a crafted avatar ID. The avatarbuilder route places its path identifier in a single-quoted image source attribute without neutralizing embedded single quotes. No authentication is required, but a user must open the crafted request; injected script runs in that user's browser context and can read or modify accessible page data.

The record

CVE
CVE-2021-4169
Published
Dec 26, 2021
Updated
Aug 3, 2024
Vendor
LiveHelperChat
Product
Live Helper Chat
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=unspecified <=3.90

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LiveHelperChat · Live Helper Chatversion=unspecified <=3.90

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.4huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

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.

Technologies

Your stack

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Your stack

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