CVE-2026-33628 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in invoiceninja/invoiceninja. A fix is available for invoiceninja/invoiceninja — see the affected versions and patch details below.
Invoice Ninja Denylist Bypass may Lead to Stored XSS via Invoice Line Items
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33628.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
invoiceninja/invoiceninjaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Vulnerability Details
Invoice line item descriptions in Invoice Ninja v5.13.0 bypass the XSS denylist filter, allowing stored XSS payloads to execute when invoices are rendered in the PDF preview or client portal.
The line item description field was not passed through purify::clean() before rendering.
Steps to Reproduce
- Login as any authenticated user
- Create or edit an invoice
- In a line item description, enter:
<img src=x onerror=alert(document.cookie)> - Save the invoice and preview it
- The XSS payload executes in the browser
Impact
- Attacker: Any authenticated user who can create invoices
- Victim: Any user viewing the invoice (including clients via the portal)
- Specific damage: Session hijacking, account takeover, data exfiltration
Proposed Fix
Fixed in v5.13.4 by the vendor by adding purify::clean() to sanitize line item descriptions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | invoiceninja/invoiceninja | all versions | 5.13.4composer require invoiceninja/invoiceninja:^5.13.4 |
Affected Products
invoice ninjainvoiceninjaDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for invoiceninja/invoiceninja, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update invoiceninja/invoiceninja to 5.13.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33628 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2026-33628 in your dependencies?
Find it across Packagist, including transitive dependencies.