CVE-2026-34366 InvoiceShelf: SSRF in Payment Receipt PDF Rendering via Unsanitised HTML in Notes Field

High 7.6 Published 31 Mar 2026 Updated 1 Apr 2026

Attackers can exploit unsanitized HTML in payment notes to trigger Server-Side Request Forgery via PDF generation, potentially accessing internal resources.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-34366?

CVE-2026-34366 is a high-severity server-side request forgery vulnerability in InvoiceShelf, published on 31 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.2.0, a Server-Side Request Forgery (SSRF) vulnerability exists in the Payment receipt PDF generation module. User-supplied HTML in the payment Notes field is passed unsanitised to the Dompdf rendering library, which will fetch any remote resources referenced in the markup. The vulnerability is exploitable directly via the PDF receipt endpoint, regardless of whether automated email attachments are enabled. This issue has been patched in version 2.2.0.

Weakness: CWE-918

Which versions are affected by CVE-2026-34366?

It affects 1 product.

Products include Invoiceshelf Invoiceshelf.

How do I fix CVE-2026-34366?

No fix has been published for CVE-2026-34366 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-34366 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34366 exists.

Sources

Also known as GHSA-38hf-fq8x-q49r.