CVE-2021-27839: Bigprof Online Invoicing System

Medium severity, CVSS 4.4. EPSS: 0.7% chance of exploitation in the next 30 days.

A CSV injection vulnerability found in Online Invoicing System (OIS) 4.3 and below can be exploited by users to perform malicious actions such as redirecting admins to unknown or harmful websites, or disclosing other clients' details that the user did not have access to.

Affected products

• Bigprof Online Invoicing System: up to and including 4.3

Published 2021-03-03. Last modified 2026-06-17.