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

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

- **Severity:** High 7.6 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** GHSA-38hf-fq8x-q49r

## 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 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-34366?

It affects 1 product.


Products: 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.

## Is CVE-2026-34366 being exploited?

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

## Other vulnerabilities in InvoiceShelf

- [CVE-2026-34365](https://insights.sbomify.com/CVE-2026-34365/): InvoiceShelf: SSRF in Estimate PDF Rendering via Unsanitised HTML in Notes Field (high 7.6)
- [CVE-2026-34367](https://insights.sbomify.com/CVE-2026-34367/): InvoiceShelf: SSRF in Invoice PDF Rendering via Unsanitised HTML in Notes Field (high 7.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34366 and fix it if it is affected.

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

Affected product: InvoiceShelf. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34366/ (Markdown: https://insights.sbomify.com/CVE-2026-34366/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34366
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34366
- OSV: https://osv.dev/vulnerability/CVE-2026-34366

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34366/
Summaries are generated and may contain mistakes; the official description above is the record.