PaperCut MF/NG: Unsafe Dynamic Class Loading in Database Connector
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.
- Published
- Aug 28, 2026
- Updated
- Sep 13, 2026
- EPSS
- 3.8% · 90th percentile
- CWE
- CWE-470
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Report tools
Action score
68
This week
Don’t wait for the next maintenance window.
- CVSS
- 37 / 40 · 9.4 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 1 / 30 · 3.8%
CISA SSVC decision
- Exploitation
- active
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · PaperCut
- 9.4
- NVD has not scored this yet; the score shown is the CNA’s.
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
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Aug 31, 2026. That signals real attacks, not theory.
Remediation deadline for government agencies: Sep 14, 2026.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| papercut | papercut mf | cpe:2.3:a:papercut:papercut_mf |
| papercut | papercut ng | cpe:2.3:a:papercut:papercut_ng |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- papercut papercut mfbefore 24.1.9
- papercut papercut mf25.0.2 and later · before 25.0.12
- papercut papercut mf26.0.2 and later · before 26.0.4
- papercut papercut ngbefore 24.1.9
- papercut papercut ng25.0.2 and later · before 25.0.12
- papercut papercut ng26.0.2 and later · before 26.0.4
Versions reported by the vendor
Affected version ranges reported by the assigning authority (PaperCut). Independent of NVD's CPE analysis and usually ahead of it.
PaperCut PaperCut MF/NG
- before 24.1.10affected · semver
- 25.0.0 and later · before 25.0.13affected · semver
- 26.0.0 and later · before 26.0.5affected · semver
Same product
papercut: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-27350This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914).KEV99Now
- CVE-2023-27351This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914).KEV83Now
- CVE-2023-2533PaperCut MF/NG 22.0.10 (Build 65996 2023-03-27) - Remote code execution via CSRFKEV74This week
- CVE-2026-81578PaperCut MF/NG: Authentication BypassKEV66This week
- CVE-2023-39143PaperCut NG and PaperCut MF before 22.1.3 on Windows allow path traversal, enabling attackers to upload, read, or delete arbitrary files.63This week
- CVE-2024-1222Incorrect authorization controls in PaperCut NG/MF APIs58Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| PaperCut PaperCut MF/NG | 24.1.10 | Vendor (CNA) |
| PaperCut PaperCut MF/NG | 25.0.13 | Vendor (CNA) |
| PaperCut PaperCut MF/NG | 26.0.5 | Vendor (CNA) |
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
- Nuclei detection template ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Metasploit module | exploit/multi/http/papercut_ng_external_user_lookup_rcePaperCut NG/MF Unauthenticated RCE (CVE-2026-81578 + CVE-2026-82078)exploit | 2026-08-27 |
| Nuclei detection template | Nuclei template CVE-2026-81578 | — |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Metasploit-2 d
- Published
- CISA KEV+2 d
- TodaySep 29, 2026+32 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- Administrator privileges are required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-470 · Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')CVSS vector
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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/
- github.com/rapid7/metasploit-framework/pull/21842
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-82078
Vendor advisories and official records. Exploit/PoC links are deliberately left out.