CVE-2026-82078
PaperCut NG/MF Unsafe Reflection Vulnerability
PaperCut NG/MF
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 31 August 2026. US federal agencies were required to remediate it by 14 September 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 1.7%, which is higher than 75.6% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Frequently asked questions
Is CVE-2026-82078 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2026-82078.
What does CVE-2026-82078 affect?
CVE-2026-82078 affects PaperCut NG/MF. 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.
How severe is CVE-2026-82078?
CVE-2026-82078 is rated CRITICAL with a CVSS base score of 9.1. EPSS puts the probability of exploitation in the next 30 days at 1.7%, higher than 75.6% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 14 September 2026.
How should organisations respond to CVE-2026-82078?
Apply the vendor patch for PaperCut NG/MF as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.