ACCORDING to CISA, the Known Exploited Vulnerabilities (KEV) Catalog is the authoritative source of vulnerabilities that have been exploited in the wild, and PaperCut NG/MF is listed with CVE-2023-27351, described as an Improper Authentication Vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.
The entry notes that the vulnerability is “Unknown” in terms of whether it is known to be used in ransomware campaigns, and it provides mitigations including applying vendor instructions, following the guidance in BOD 22-01 for cloud services, or discontinuing use of the product if mitigations are unavailable. Date Added for this item is 20 April 2026, with a Due Date of 04 May 2026. The KEV catalog is available in CSV, JSON, and JSON Schema formats, and the page itself shows a single entry for PaperCut | NG/MF under CVE-2023-27351.