CVE-2026-33628

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

1. Login as any authenticated user
2. Create or edit an invoice
3. In a line item description, enter: <img src=x onerror=alert(document.cookie)>
4. Save the invoice and preview it
5. The XSS payload executes in the browser

Proposed Fix

Fixed in v5.13.4 by the vendor by adding purify::clean() to sanitize line item descriptions.

• 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

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2026-33628 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.13.4); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-33628? CVE-2026-33628 is a medium-severity cross-site scripting (XSS) vulnerability in invoiceninja/invoiceninja (composer), affecting versions < 5.13.4. It is fixed in 5.13.4. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2026-33628? CVE-2026-33628 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of invoiceninja/invoiceninja are affected by CVE-2026-33628? invoiceninja/invoiceninja (composer) versions < 5.13.4 is affected.
4. Is there a fix for CVE-2026-33628? Yes. CVE-2026-33628 is fixed in 5.13.4. Upgrade to this version or later.
5. Is CVE-2026-33628 exploitable, and should I be worried? Whether CVE-2026-33628 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-33628 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-33628? Upgrade invoiceninja/invoiceninja to 5.13.4 or later.