CVE-2024-12451Network attack vector

Stored XSS via unescaped shortcode attributes

Published Jan 30, 2025 · Updated Apr 8, 2026

Stored XSS in Proxymis HTML5 Chat 1.07 and earlier allows remote authenticated users to inject scripts through HTML5CHAT attributes. The shortcode handler accepts user-controlled dimensions without sufficient sanitization and places them into generated markup without output escaping. Contributor-level access is required to save the payload, which executes in a visitor's browser whenever the affected page is opened.

CVSS severity6.4
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Proxymis HTML5 Chat 1.07 and earlier allows remote authenticated users to inject scripts through HTML5CHAT attributes. The shortcode handler accepts user-controlled dimensions without sufficient sanitization and places them into generated markup without output escaping. Contributor-level access is required to save the payload, which executes in a visitor's browser whenever the affected page is opened.

The record

CVE
CVE-2024-12451
Published
Jan 30, 2025
Updated
Apr 8, 2026
Vendor
Proxymis
Product
HTML5 Chat
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2026Record 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=0 <=1.07

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Proxymis · HTML5 Chatversion=0 <=1.07

Published CVSS scores

6.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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