CVE-2026-82078
KEV: known exploited SSVC: activePaperCut MF/NG: Unsafe Dynamic Class Loading in Database Connector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
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:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Attack conditions and impact
Derived from the NVD CVSS 3.1 vector| Metric | Value | Meaning |
|---|---|---|
| Attack vector AV | N | Network |
| Attack complexity AC | L | Low (easy) |
| Privileges required PR | H | Administrator |
| User interaction UI | N | None |
| Scope S | C | Changed (affects other components) |
| Confidentiality C | H | High |
| Integrity I | H | High |
| Availability A | H | High |
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
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.
CISA KEV entry
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.
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.
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
CVSS assessments
| Provider | Version | Score | Vector |
|---|---|---|---|
| NVD / eb41dac7-0af8-4f84-9f6d-0272772514f4 (Secondary) | 4.0 | 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 |
| NVD / [email protected] (Primary) | 3.1 | 9.1 CRITICAL | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
| CNA / PaperCut | 4.0 | 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 |
Affected products and packages
CNA (CVE.org)
| Vendor | Product | Versions |
|---|---|---|
| PaperCut | PaperCut MF/NG | affected: 0 … < 24.1.10 affected: 25.0.0 … < 25.0.13 affected: 26.0.0 … < 26.0.5 default: unaffected |
NVD CPE (6)
Show CPE list
| Vendor | Product | Range | CPE |
|---|---|---|---|
| papercut | papercut_mf | < 24.1.9 | cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:* |
| papercut | papercut_mf | >= 25.0.2, < 25.0.12 | cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:* |
| papercut | papercut_mf | >= 26.0.2, < 26.0.4 | cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:* |
| papercut | papercut_ng | < 24.1.9 | cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:* |
| papercut | papercut_ng | >= 25.0.2, < 25.0.12 | cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:* |
| papercut | papercut_ng | >= 26.0.2, < 26.0.4 | cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:* |
Linux distribution status
References (3)
- https://github.com/rapid7/metasploit-framework/pull/21842 NVD, ADP CISA-ADP Issue TrackingPatchexploit
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-82078 NVD, ADP CISA-ADP PatchThird Party AdvisoryUS Government Resourcegovernment-resource
- https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ NVD, CNA PatchVendor Advisory