CVE-2026-84432Network attack vector

Board data modification via missing CSRF validation

Published Sep 10, 2026 · Updated Sep 10, 2026

Cross-site request forgery in Concrete CMS 9.0.0 through 9.5.2 allows attackers to modify board custom-slot data remotely. The Boards custom slot dialog's saveTemplate() action accepts slot and template values without validating an anti-CSRF token, then creates a board_slot_proxy Block and dispatches AddCustomSlotToBoardCommand before rendering. The victim must have an active session with board-edit permission and load an attacker-controlled request; the resulting write runs under that user's authority.

CVSS severity5.3
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

Cross-site request forgery in Concrete CMS 9.0.0 through 9.5.2 allows attackers to modify board custom-slot data remotely. The Boards custom slot dialog's saveTemplate() action accepts slot and template values without validating an anti-CSRF token, then creates a board_slot_proxy Block and dispatches AddCustomSlotToBoardCommand before rendering. The victim must have an active session with board-edit permission and load an attacker-controlled request; the resulting write runs under that user's authority.

The record

CVE
CVE-2026-84432
Published
Sep 10, 2026
Updated
Sep 10, 2026
Vendor
Concrete CMS
Product
Concrete CMS
Classifications
T1204
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 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=9.0.0 <=9.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Concrete CMS · Concrete CMSversion=9.0.0 <=9.5.2

Published CVSS scores

5.3Concrete CMS security teamCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

T1204User Execution

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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