What is CVE-2026-82078?
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.
The record classifies CVE-2026-82078 under weakness class CWE-470. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs high-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 47 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.1 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - CVSS v4.0 base score
- 9.4
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 - EPSS (FIRST)
- 63.5% probability of exploitation in the next 30 days, higher than 99.1% of all scored CVEs
- CISA KEV
- Listed since 2026-08-31, federal remediation deadline 2026-09-14
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2026-08-28, last modified 2026-09-13
Is CVE-2026-82078 being exploited?
CISA added CVE-2026-82078 to the Known Exploited Vulnerabilities catalog on 2026-08-31, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-09-14 under BOD 22-01. It currently carries a trending score of 64 in the Threadlinqs vulnerability feed.
Affected products and versions
- PaperCut: MF/NG
How to fix CVE-2026-82078
The record marks a vendor fix as available for CVE-2026-82078. Patch reference: https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/. Vendor advisory: https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/. Because CVE-2026-82078 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-09-14. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-82078
1 tracked threat in the Threadlinqs corpus references CVE-2026-82078, either in the campaign’s CVE list or as an indicator on the campaign record.
- PaperCut NG/MF Chained Zero-Day RCE (CVE-2026-82078 & CVE-2026-81578) Under Active Exploitation — CRITICAL · 2026-08-28
Sources
Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.