CVE-2026-82078

Published Aug 28, 2026

Last updated a month ago

Exploit known CVSS critical 9.4

web application

SMTP

PaperCut MF

PaperCut NG

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-82078 identifies an unsafe dynamic class-loading vulnerability present in the database connection utilities of PaperCut MF and PaperCut NG. This flaw allows the application to instantiate database driver classes using configurable driver names without proper validation against an approved allowlist of drivers. When exploited, particularly in conjunction with CVE-2026-81578 (an improper access control vulnerability), this vulnerability can enable an unauthenticated attacker to execute arbitrary Java bytecode. This chain of vulnerabilities ultimately facilitates pre-authentication remote code execution within the PaperCut Application Server.

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.
Source: eb41dac7-0af8-4f84-9f6d-0272772514f4
NVD status: Analyzed
Products: papercut_mf, papercut_ng

Risk scores

CVSS 4.0

Type: Secondary
Base score: 9.4
Impact score: -
Exploitability score: -
Vector string: 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
Severity: CRITICAL

CVSS 3.1

Type: Primary
Base score: 9.1
Impact score: 6
Exploitability score: 2.3
Vector string: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Severity: CRITICAL

Known exploits

Data from CISA

Vulnerability name: PaperCut NG/MF Unsafe Reflection Vulnerability
Exploit added on: Aug 31, 2026
Exploit action due: Sep 14, 2026
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.

Weaknesses

eb41dac7-0af8-4f84-9f6d-0272772514f4: CWE-470

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "F2AF3AB4-FD10-4DE1-B906-011F45948BD0",
            "versionEndExcluding": "24.1.9",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "8F6ED0B8-62DC-4CF9-9810-2CCB824FBCA8",
            "versionEndExcluding": "25.0.12",
            "versionStartIncluding": "25.0.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "51E91B81-E311-4BB9-A753-671F0C59E7F7",
            "versionEndExcluding": "26.0.4",
            "versionStartIncluding": "26.0.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "44FCDCDE-4126-4F4F-89FC-D44924F45C82",
            "versionEndExcluding": "24.1.9",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "9E727ABD-0007-424D-AB07-FB7816E43792",
            "versionEndExcluding": "25.0.12",
            "versionStartIncluding": "25.0.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "3938B71A-CB14-4017-A037-7D5F08DAFB13",
            "versionEndExcluding": "26.0.4",
            "versionStartIncluding": "26.0.2",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.