PaperCut NG/MF Improper Authentication Vulnerability

Critical Threat Advisory: This vulnerability is documented in active Ransomware campaigns. Immediate remediation required.

Technical Severity

CVSS v3.1 Metrics

HIGH

7.5 / 10

Minimal Risk Critical

Vector Specification

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

Exploitation Likelihood

EPSS Prediction

83.28 %

Predictive Probability

Percentile Rank

99.3 th

Documented as more likely to be exploited than 99.3% of known CVEs.

Detection Date

Apr 20, 2026

Remediation Due

May 04, 2026

CISA Catalog Active

Threat Analysis

PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.

Remediation Directive

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

External Intelligence

https://www.papercut.com/kb/Main/PO-1216-and-PO-1219

NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2023-27351