Actively exploited in the wild
PaperCut NG/MF Missing Authentication for Critical Function Vulnerability
PaperCut - NG/MF · Listed in the CISA KEV since 2026-08-31. This indicates confirmed attacks in production environments.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVE-2026-81578
CriticalCVSS 9.8KEVExploitation Probability (EPSS)
Elevated risk75th percentile - higher than 75% of all known CVEs
Summary
Improper access control vulnerability in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions before access validation completes, allowing modification of certain system configurations.
Risk Assessment
An unauthenticated attacker can alter system configuration, potentially leading to security breaches, service disruptions, or unauthorized changes.
Recommendation
Apply available security updates from PaperCut and restrict access to the management interface to trusted networks only.
Other vulnerabilities in PaperCut MF/NG
See all- CVE-2026-82078CriticalActively exploited
An unsafe dynamic class loading vulnerability exists in the database connection utilities of PaperCut MF and PaperCut NG. The application instantiates database driver classes based on configurable driver names without validating against an allowlist. If an attacker can manipulate system configuration, this enables execution of arbitrary Java bytecode under the security context of the PaperCut server process.
- CVE-2026-87739Medium
An improper authentication vulnerability in PaperCut MF/NG allows an unauthenticated remote attacker to trigger report generation. By submitting report generation requests without valid credentials, an attacker can generate reports and gain unauthorized access to sensitive information.
Original NVD description (English source)
An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS