CVEvulnerability

CVE-2026-82078

9.4 CRITICAL Known exploited Published 2026-08-28 Modified 2026-09-14 Official page ↗

CISA Known Exploited Vulnerability

PaperCut NG/MF Unsafe Reflection Vulnerability — PaperCut NG/MF

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.

Added to KEV: 2026-08-31
Remediation due: 2026-09-14
Ransomware use: Unknown
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

Status: Analyzed
Published: 2026-08-28
Last modified: 2026-09-14
Assigner: eb41dac7-0af8-4f84-9f6d-0272772514f4
CVSS 4.0 (eb41dac7-0af8-4f84-9f6d-0272772514f4): 9.4 CRITICAL — CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected]): 9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weaknesses: CWE-470

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.

Affected configurations

• papercut papercut mf (< 24.1.9) • papercut papercut mf (>= 25.0.2 < 25.0.12) • papercut papercut mf (>= 26.0.2 < 26.0.4) • papercut papercut ng (< 24.1.9) • papercut papercut ng (>= 25.0.2 < 25.0.12) • papercut papercut ng (>= 26.0.2 < 26.0.4)

Weakness · CWE (1)

CWE-470 Use of Externally-Controlled Input to Select Classes or Code weakness

References