CVE-2026-8414Network attack vector

Unauthorized event duplication via cross-site requests

Published May 21, 2026 · Updated May 21, 2026

Cross-site request forgery in Concrete CMS 9.0 through 9.5.0 allows remote attackers to duplicate events through crafted requests. The duplicate-event dialog controller processes a state-changing request without sufficiently verifying that the authenticated user intended it. Exploitation requires a logged-in user's browser to submit the cross-site request, and the documented consequence is limited to unauthorized event duplication.

CVSS severity2.3
Low
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Concrete CMS 9.0 through 9.5.0 allows remote attackers to duplicate events through crafted requests. The duplicate-event dialog controller processes a state-changing request without sufficiently verifying that the authenticated user intended it. Exploitation requires a logged-in user's browser to submit the cross-site request, and the documented consequence is limited to unauthorized event duplication.

The record

CVE
CVE-2026-8414
Published
May 21, 2026
Updated
May 21, 2026
Vendor
Concrete CMS
Product
Concrete CMS
Classifications
CWE-1275, CWE-352, CAPEC-1
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2026CVE publishedPublication date reported by the CVE source.
  2. May 21, 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=9.0 <=9.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Concrete CMS · Concrete CMSversion=9.0 <=9.5.0

Published CVSS scores

2.3Concrete CMS security teamCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1275Sensitive Cookie with Improper SameSite Attribute
CWE-352Cross-Site Request Forgery (CSRF)
CAPEC-1Accessing Functionality Not Properly Constrained by ACLs

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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