April 20, 2026 · Applied Cybernetics Group
CVE-2023-27351 — PaperCut NG/MF
known ransomware use
PaperCut NG/MF Improper Authentication Vulnerability
- Added to KEV
2026-04-20- Federal due date
2026-05-04- Vendor
- PaperCut
- Product
- NG/MF
- EPSS
- 99.6th percentile (score 0.781, as of
2026-10-04) - NVD CVSS v3.1
- 7.5 (HIGH)
- Ransomware use
- Known
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2023-27351
CISA short description
PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
NVD description
This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.