CVE Intelligence
CISA KEV Critical

CVE-2026-82078 — PaperCut NG/MF Unsafe Reflection Vulnerability

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 Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: PaperCut

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Aug 31, 2026 Metasploit modules · 1
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • Public exploit/PoC (metasploit)+12
  • EPSS 63.5% (30-day exploitation probability)+15
  • Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Aug 31, 2026
EPSS FIRST
63.53%
ahead of 99% of scored CVEs · Oct 14, 2026
Affects
PaperCut
Papercut Mf and 2 more
CVSS base
9.1
Critical · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — www.papercut.com (NIST National Vulnerability Database)
  • Documented patch — github.com (NIST National Vulnerability Database)
  • Documented patch — www.cisa.gov (NIST National Vulnerability Database)

CISA required action CISA

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.

US federal deadline: Sep 14, 2026 — passed 31 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (PaperCut Papercut Mf, PaperCut PaperCut MF/NG, PaperCut Papercut Ng).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. Apply the fixed version or the patch documented under Remediation.
  4. EPSS ahead of 99% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
PaperCut Papercut Mf < 24.1.9≥ 25.0.2 and < 25.0.12≥ 26.0.2 and < 26.0.4 Vulnerable NIST National Vulnerability Database
PaperCut PaperCut MF/NG < 24.1.10≥ 25.0.0 and < 25.0.13≥ 26.0.0 and < 26.0.5 Vulnerable CVE Program (cve.org) e CISA ADP
PaperCut Papercut Ng < 24.1.9≥ 25.0.2 and < 25.0.12≥ 26.0.2 and < 26.0.4 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.4 CVSS 4.0 Critical — — eb41dac7-0af8-4f84-9f6d-0272772514f4 via NIST National Vulnerability Database
9.4 CVSS 4.0 Critical — — PaperCut via CVE Program (cve.org) e CISA ADP
9.1 CVSS 3.1 Critical 2.3 6.0 nvd@nist.gov via NIST National Vulnerability Database
9.1 CVSS 3.1 Critical — — GitHub, Inc. via GitHub Security Advisories
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-470

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Aug 31, 2026
Federal deadline
Sep 14, 2026
passed 31 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Metasploit modules

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 63.53%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Hunt retroactively in logs from before Aug 31, 2026 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · papercut/papercut mf/ng
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • Affected products added · papercut/papercut mf, papercut/papercut ng
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 9.1
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Added to CISA KEV catalog
    Aug 30, 2026 · CISA
  • CVE published
    Aug 28, 2026 · PaperCut

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

6 on the record

Elsewhere on this site

PaperCut
every CVE for this vendor
2026-08
what else CISA listed that month
CWE-470
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-81578 PaperCut NG/MF Missing Authentication for Critical Function Vulnerability KEV Aug 28, 2026
  • CVE-2026-6180 PaperCut MF: Card truncation on HP readers May 5, 2026
  • CVE-2026-6418 PaperCut NG/MF: Path Traversal in Shared Account Synchronization May 5, 2026
  • CVE-2026-4794 Multiple cross-site scripting (XSS) vulnerabilities in PaperCut NG/MF Mar 30, 2026
  • CVE-2026-5115 Session hijacking in PaperCut NG/MF embedded application for Konica Minolta devices Mar 30, 2026
  • CVE-2023-2533 PaperCut NG/MF Cross-Site Request Forgery (CSRF) Vulnerability KEV Jun 20, 2023

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-82078 is "PaperCut NG/MF Unsafe Reflection Vulnerability", rated Critical. It affects Papercut Mf (PaperCut); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.1 describes technical severity. EPSS 63.53% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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