CVE-2026-81909 - 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

CVE-2026-81909 - 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

https://cvefeed.io/rssfeed/latest.atom / Fri, 09/11/2026 - 22:31
CVE ID :CVE-2026-81909
Published : Sept. 11, 2026, 6:16 p.m. | 49 minutes ago
Description :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
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