CVE-2026-81896Network attack vectorHinoki check available

Stored XSS via unescaped form question labels

Published Sep 15, 2026 · Updated Sep 15, 2026

Stored cross-site scripting in Concrete CMS before 9.5.3 allows remote authenticated users to execute script in an administrator's browser. The Dashboard Form Submissions report renders user-defined Form block question labels as column headers without HTML entity encoding. A rogue editor must store a crafted label, and an administrator must open that form's submissions report, allowing the script to act in the administrator's browser.

CVSS severity8.4
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored cross-site scripting in Concrete CMS before 9.5.3 allows remote authenticated users to execute script in an administrator's browser. The Dashboard Form Submissions report renders user-defined Form block question labels as column headers without HTML entity encoding. A rogue editor must store a crafted label, and an administrator must open that form's submissions report, allowing the script to act in the administrator's browser.

The record

CVE
CVE-2026-81896
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Concrete CMS
Product
Concrete CMS
Classifications
CWE-79, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 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=5.0.0 <=9.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Concrete CMS · Concrete CMSversion=5.0.0 <=9.5.2

Published CVSS scores

8.4Concrete CMSCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/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 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')
T1565.001Stored Data Manipulation

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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