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CVE-2023-27351

7.5
HIGHCVSS v3.1 Base Score
83.28%
HIGH RiskEPSS (99th percentile)
KEV

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.

Published: 4/20/2023
Modified: 4/21/2026
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ACTIVELY EXPLOITED IN THE WILD

This vulnerability is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

Vulnerability Name:

PaperCut NG/MF Improper Authentication Vulnerability

Vendor / Product:

PaperCut NG/MF

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.

Due Date: 5/4/2026(OVERDUE)
Ransomware Campaign Use
Added to KEV:

4/20/2026

Notes:

https://www.papercut.com/kb/Main/PO-1216-and-PO-1219 ; https://nvd.nist.gov/vuln/detail/CVE-2023-27351

Vulnerability Summary

CVSS v3 Score

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Score (Exploitation Probability)

83.28%HIGH Exploitation Risk
99th percentile

This vulnerability has a 83.28% probability of being exploited in the next 30 days, ranking higher than 99% of all scored CVEs.

CWE Classification

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Same Weakness Type(CWE-287)

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