CVE-2026-81909 (GCVE-0-2026-81909)

Vulnerability from cvelistv5 – Published: 2026-09-11 17:49 – Updated: 2026-09-11 17:58
VLAI
Title
Concrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the orphaned-block alias route, allowing an authenticated editor to disclose and force-delete arbitrary blocks
Summary
Concrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the block alias route (Process::alias() in concrete/controllers/backend/block/process.php).It does not verify that the referenced block is genuinely orphaned on the target page, nor that the caller holds any permission over the source block. A user granted only an area-scoped add_block_to_area delegation on their own page can therefore pass any block ID on the site: the source block's content is duplicated into an area the rogue editor controls, disclosing that content, and the original block is then force-deleted in the same request, destroying arbitrary site content. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.9 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.
Severity
5.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-11 17:58 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Concrete CMS Concrete CMS Affected: 9.0.0 , ≤ 9.5.2 (git)
guessed Create a notification for this product.
Credits
tenzai
Show details on NVD website
To clipboard 

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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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