CVE-2026-18372Network attack vector

UI manipulation via CSS injection

Published Aug 19, 2026 · Updated Aug 20, 2026

CSS injection in M-Files Web before 26.8.16330.2 allows remote authenticated users to alter the UI shown to other vault users. Public advisories do not disclose the exact field or code path, but M-Files Web accepts untrusted CSS and reuses it during later page rendering for other users. Exploitation requires vault administrator privileges and another user loading the affected web interface, with published scoring limiting the documented impact to UI integrity rather than script execution or server compromise.

CVSS severity4.8
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSS injection in M-Files Web before 26.8.16330.2 allows remote authenticated users to alter the UI shown to other vault users. Public advisories do not disclose the exact field or code path, but M-Files Web accepts untrusted CSS and reuses it during later page rendering for other users. Exploitation requires vault administrator privileges and another user loading the affected web interface, with published scoring limiting the documented impact to UI integrity rather than script execution or server compromise.

The record

CVE
CVE-2026-18372
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
M-Files
Product
M-Files Web
Classifications
CWE-79
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 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 <26.8.16330.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

M-Files · M-Files Webversion=0 <26.8.16330.2

Published CVSS scores

4.8M-Files CorporationCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

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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