CVE-2021-43032Public exploitNetwork attack vector

Stored XSS via unsanitized advertisement HTML

Published Nov 3, 2021 · Updated Aug 4, 2024

Stored XSS in XenForo 2.2.7 and earlier allows remote authenticated users to execute scripts in visitors' browsers via advertisements. The Advertising function stores administrator-supplied HTML without neutralizing script content, then renders it across client-facing pages. An attacker needs admin-panel access, and a visitor must load an affected page; the script runs in the visitor's XenForo origin and can alter page content or access browser-visible data.

CVSS severity4.8
Medium
EPSS probability0.91%
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 XenForo 2.2.7 and earlier allows remote authenticated users to execute scripts in visitors' browsers via advertisements. The Advertising function stores administrator-supplied HTML without neutralizing script content, then renders it across client-facing pages. An attacker needs admin-panel access, and a visitor must load an affected page; the script runs in the visitor's XenForo origin and can alter page content or access browser-visible data.

The record

CVE
CVE-2021-43032
Published
Nov 3, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Nov 3, 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 privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

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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