CVE WatchSep 14, 2026

CVE-2026-82078

PaperCut NG/MF Unsafe Reflection Vulnerability

CVSS

9.1

Critical

EPSS

63.5%

p99

KEV

YES

Aug 31, 2026

Exploit Today

0-100

Published: Aug 28, 2026 · Last modified: Sep 14, 2026 · CWE-470

EPSS · 30d

1.7%EPSS · 30 days63.5%

2026-09-142026-10-12

KEV catalog record

Product

PaperCut / NG/MF

Vulnerability

PaperCut NG/MF Unsafe Reflection Vulnerability

Added to KEV

Aug 31, 2026

Remediate by

Sep 14, 2026

Known ransomware use

Summary description

PaperCut NG/MF contains an unsafe reflection vulnerability that allows an attacker to manipulate system configuration parameters and execute arbitrary Java bytecode residing on the application classpath under the security context of the PaperCut server process. This vulnerability can be chained with CVE-2026-81578.

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.

Notes

https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/?lid=2oneu2wt0ct4 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-82078

Technical description

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 of approved drivers. If an attacker can manipulate system configuration parameters, this enables the execution of arbitrary Java bytecode residing on the application classpath under the security context of the PaperCut server process.

Official references

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