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CVE-2023-27351

PaperCut NG/MF Improper Authentication Vulnerability

PaperCut NG/MF CWE-287

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.

CVSS Score
8.2
High
EPSS — Exploit Probability
66%
Riskier than 99% of all CVEs
Exploitation
Confirmed in the wild
Used in ransomware campaigns
Remediation
Patch available
Federal deadline 2026-05-04
CISA 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. Deadline for federal agencies: 2026-05-04.

NVD entry Vendor patch PoC / advisory CISA KEV

6 articles across 6 outlets · first covered Apr 6, 2026 · latest Apr 21, 2026

Associated threat actors

DEV-0950 Storm-1175

Coverage timeline