CVE-2026-87928Public exploitNetwork attack vector

Stored XSS via unrestricted HTML file upload

Published Sep 9, 2026 · Updated Sep 9, 2026

Stored cross-site scripting in MaxSite CMS 0.94 through 109.6 allows remote authenticated users to run scripts in visitors' browsers. The admin_page upload handler accepts HTML filenames and raw request bodies, writes them beneath uploads/_pages/, and serves the files without neutralizing scripts. Any logged-in account can plant persistent content, but script execution requires a visitor to open the uploaded file and is bounded to that visitor's browser context.

CVSS severity5.1
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in MaxSite CMS 0.94 through 109.6 allows remote authenticated users to run scripts in visitors' browsers. The admin_page upload handler accepts HTML filenames and raw request bodies, writes them beneath uploads/_pages/, and serves the files without neutralizing scripts. Any logged-in account can plant persistent content, but script execution requires a visitor to open the uploaded file and is bounded to that visitor's browser context.

The record

CVE
CVE-2026-87928
Published
Sep 9, 2026
Updated
Sep 9, 2026
Vendor
MaxSite
Product
MaxSite CMS
Classifications
CWE-434, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 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=0.94 <=109.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MaxSite · MaxSite CMSversion=0.94 <=109.6

Published CVSS scores

5.1VulnCheck CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
5.4VulnCheck CNACVSS: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.

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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 exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1189Drive-by Compromise

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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