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Known exploited vulnerability

CVE-2026-82078

criticalCVSS 4.0 9.4In CISA KEVEPSS 63%Published · PaperCut

The short answer

CVE-2026-82078 affects PaperCut PaperCut MF/NG and is rated critical (CVSS 9.4). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-08-31: attackers are using it, so patch it first. The vendor has linked a patch.

What it is

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.

Weakness: CWE-470.

Severity

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

Exploited (CISA KEV)

Yes, since Aug 31, 2026

Federal due date Sep 14, 2026

EPSS, next 30 days

63%

Higher than 99% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
High
User interaction
None
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

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…

Affected products

PaperCut MF/NG. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-82078 being exploited?

Yes. CISA added CVE-2026-82078 to its Known Exploited Vulnerabilities catalog on 2026-08-31, with a federal remediation due date of 2026-09-14.

How do I fix CVE-2026-82078?

CISA's 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…

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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