Concrete CMS 9 through 9.5.2 did not validate a CSRF token in the orphaned block removal panel action (removeOrphanedBlocks). (CVE-2026-81902)
Concrete CMS versions 9 through 9.5.2 contain a vulnerability where the orphaned block removal panel action (removeOrphanedBlocks) does not validate a CSRF token. This allows a remote attacker to craft a request that, when executed by an authenticated user with edit permissions, can delete all blocks on the current page version, including permanent removal from the global Blocks table and associated block-type data tables. This results in permanent content destruction.
AI Analysis
Technical Summary
Concrete CMS versions 9 through 9.5.2 fail to validate a Cross-Site Request Forgery (CSRF) token in the removeOrphanedBlocks action of the orphaned block removal panel. An attacker can exploit this by tricking an authenticated user with edit permissions into loading a malicious request, causing deletion of all blocks on the page's current version. Blocks not aliased elsewhere are also removed from the global Blocks table and their block-type data tables, leading to permanent content loss. The vulnerability has a CVSS v4.0 score of 7.1, indicating high severity.
Potential Impact
Successful exploitation results in permanent deletion of page content blocks, including those not aliased to other pages or scrapbook entries. This causes irreversible content loss on the targeted page version, impacting site integrity and availability of content.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict edit permissions to trusted users and avoid loading untrusted content that could trigger the vulnerable action.
Concrete CMS 9 through 9.5.2 did not validate a CSRF token in the orphaned block removal panel action (removeOrphanedBlocks). (CVE-2026-81902)
Description
Concrete CMS versions 9 through 9.5.2 contain a vulnerability where the orphaned block removal panel action (removeOrphanedBlocks) does not validate a CSRF token. This allows a remote attacker to craft a request that, when executed by an authenticated user with edit permissions, can delete all blocks on the current page version, including permanent removal from the global Blocks table and associated block-type data tables. This results in permanent content destruction.
CVSS v4.0
Affected software
pkg:github/concretecms/concrete5Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Concrete CMS versions 9 through 9.5.2 fail to validate a Cross-Site Request Forgery (CSRF) token in the removeOrphanedBlocks action of the orphaned block removal panel. An attacker can exploit this by tricking an authenticated user with edit permissions into loading a malicious request, causing deletion of all blocks on the page's current version. Blocks not aliased elsewhere are also removed from the global Blocks table and their block-type data tables, leading to permanent content loss. The vulnerability has a CVSS v4.0 score of 7.1, indicating high severity.
Potential Impact
Successful exploitation results in permanent deletion of page content blocks, including those not aliased to other pages or scrapbook entries. This causes irreversible content loss on the targeted page version, impacting site integrity and availability of content.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict edit permissions to trusted users and avoid loading untrusted content that could trigger the vulnerable action.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-xhpm-mjpp-w9gx
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-81902"]
- Database Specific Severity
- HIGH
- Cvss Version
- 4.0
Threat ID: 6aa8a1a555bf5e2cf5f3d4ef
Added to database: 09/15/2026, 01:38:45 UTC
Last enriched: 09/15/2026, 01:51:50 UTC
Last updated: 09/15/2026, 05:21:27 UTC
Views: 3
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