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CVE-2026-82078criticalunder attackCWE-470

PaperCut MF/NG: Unsafe Dynamic Class Loading in Database Connector

93Vexday Risk Score

Patch now. It under exploitation confirmed by CISA and has a working public exploit.

ssvc Actcvss 9.4epss 0.9%
from disclosure to weapon0 days
Published on NVDAug 28
metasploitAug 27
CISA KEVAug 28
exploitation probability
0.9%top 42% of all CVEs
observed exploitation
yesCISA + VulnCheck
1 public exploit(s)
Action required by CISAfederal deadline: 2026-09-14

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.

In short

PaperCut MF/NG allows attackers to run malicious code on the server by manipulating database driver settings, because the application doesn't validate which database drivers it loads. This gives attackers complete control over the server if they can change the configuration.

Technical detail

The vulnerability stems from unsafe dynamic class loading in PaperCut's database connector that instantiates driver classes based on user-configurable parameters without allowlist validation (CWE-470). An attacker with configuration access can specify arbitrary Java classes from the application classpath, achieving remote code execution under the PaperCut server's security context.

Summary generated and translated by AI from the official 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.
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
PaperCut · PaperCut MF/NG
public PoCs found — 1
cve_referencegithub.com/rapid7/metasploit-framework/pull/21842unverified
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
https://github.com/rapid7/metasploit-framework/pull/21842https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-82078https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/