Known Exploited Vulnerability

CVE-2023-27351

PaperCut NG/MF Improper Authentication Vulnerability

Ransomware campaign 2 public exploits Added 20 Apr 2026 Due 04 May 2026 · 90 days ago
VendorPaperCut
ProductNG/MF
WeaknessCWE-287
RansomwareKnown use

What the flaw is

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

Description as published by CISA. We have not independently reproduced it.

What CISA requires

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

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

2 public repositories referencing this CVE have been catalogued on GitHub. Treat this as a strong signal to prioritise patching, not as a verified working exploit — many such repositories are scanners, write-ups or forks rather than functional code.

Vendor advisories

Primary sources

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Source: CISA KEV catalog · last verified July 31, 2026. Rebuilt automatically twice a day.