CVE-2026-82078
CriticalExploitedPublic exploitAn unsafe dynamic class loading vulnerability exists in the database connection utilities of PaperCut MF and PaperCut NG.
Published Aug 28, 2026 · Updated Sep 14, 2026
Key Facts
Patch immediately- CVE-2026-82078 is a critical-severity vulnerability (CVSS 9.4 v4) affecting Papercut Mf, Papercut Ng, PaperCut MF/NG.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 27, 2026. Public exploit code is available.
- EPSS estimates a 64% probability of exploitation in the next 30 days.
- Fixed versions are available, including PaperCut MF/NG 24.1.10, PaperCut MF/NG 24.1.10, 25.0.13, 26.0.5, PaperCut MF/NG 25.0.13.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v4
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 (30-day exploit likelihood)
64%
Higher than 99.2% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Aug 31, 2026 | Sep 14, 2026 | Not reported |
| Industry KEV feed | Aug 28, 2026 | Sep 14, 2026 | Not reported |
| CIRCL KEV | Aug 27, 2026 | Sep 14, 2026 | Not reported |
| ENISA EUVD | Aug 27, 2026 | n/a | Not reported |
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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Papercut MfPapercut | See advisory | 24.1.9 |
| Papercut NgPapercut | See advisory | 24.1.9 |
| PaperCut MF/NG | >= 25.0.0 | 24.1.10, 25.0.13, 26.0.5 |
Patched Releases
PaperCut MF/NG
24.1.10, 24.1.10, 25.0.13, 26.0.5, 25.0.13, 26.0.5
Papercut Mf
24.1.9, 25.0.12, 26.0.4
Papercut Ng
24.1.9, 25.0.12, 26.0.4
Timeline
Added to CIRCL KEV
Aug 27, 2026
Added to ENISA EUVD
Aug 27, 2026
Publicly disclosed
Aug 28, 2026
Added to Industry KEV feed
Aug 28, 2026
Added to CISA KEV
Aug 31, 2026
Last updated
Sep 14, 2026
Weakness Type
- CWE-470 Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
References
- exploitVulnCheck exploitation report
- exploitMSF papercut_ng_external_user_lookup_rce.rb
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
An unsafe dynamic class loading vulnerability exists in the database connection utilities of PaperCut MF and PaperCut NG.
Affected: Papercut Mf; Papercut Ng; PaperCut MF/NG versions >= 25.0.0. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 27, 2026.
Yes. It was added on Aug 31, 2026 with a federal remediation due date of Sep 14, 2026.
Public exploit code is available.
Fixed versions are available, including PaperCut MF/NG 24.1.10, PaperCut MF/NG 24.1.10, 25.0.13, 26.0.5, PaperCut MF/NG 25.0.13.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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