CVE-2026-82078 is a critical-severity (CVSS 9.1) CWE-470 vulnerability in papercut papercut mf. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-08-31) — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.
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…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-08-31. Federal agencies were required to remediate by 2026-09-14.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2026-82078.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-82078 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.
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 Products
papercut mfpapercutpapercut ngpapercutDetection & mitigation playbook
Vendor / applianceDetect
Inventory every papercut papercut mf deployment and check each version against the affected-products list above.
Fix
Apply the papercut papercut mf security patch or hotfix for CVE-2026-82078 on the affected version, following the vendor advisory for your exact build.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2026-82078 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.