CVE-2026-55561

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CVE-2026-55561

Summary: InvoicePlane: Guest user IDOR in quote approval and rejection

Details: InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. Prior to 1.7.2-beta-1, guest users can approve or reject quotes belonging to any client, not just their assigned clients. The `approve()` and `reject()` methods in the Guest Quotes controller, `application/modules/guest/controllers/Quotes.php`, call `approve_quote_by_id($quote_id)` and `reject_quote_by_id($quote_id)` directly without the `where_in('ip_quotes.client_id', $this->user_clients)` scoping that sibling methods use. A guest user assigned to one client can change another client's quote status by supplying sequential integer `quote_id` values, and `email_quote_status()` also sends notification emails. Additionally, `generate_pdf()` calls `mark_viewed($quote_id)` before checking the client scope, allowing a guest user to mark another client's quote as viewed. These issues are fixed in version 1.7.2-beta-1 and the subsequent stable version 1.7.2.

References: https://github.com/InvoicePlane/InvoicePlane/releases/tag/v1.7.2, https://github.com/InvoicePlane/InvoicePlane/releases/tag/v1.7.2-beta-1, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55561.json, https://github.com/InvoicePlane/InvoicePlane/security/advisories/GHSA-6xj3-274m-4mvg, https://nvd.nist.gov/vuln/detail/CVE-2026-55561, https://github.com/InvoicePlane/InvoicePlane/commit/424dc44eb54030b93176bb08cba07ba12d7ae451, https://github.com/InvoicePlane/InvoicePlane/commit/fca7792a24de0a749d881cbbe4af6f58e9545d20, https://github.com/InvoicePlane/InvoicePlane/pull/1413, https://github.com/InvoicePlane/InvoicePlane/pull/1471