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Response snapshot Oct 26, 2026, 23:51 UTC

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VulnerabilityCVE-2026-82078Known exploitation

PaperCut NG/MF Unsafe Reflection Vulnerability

PaperCut NG/MF contains an unsafe reflection vulnerability that allows an attacker to manipulate system configuration parameters and execute arbitrary Java bytecode residing on the application classpath under the security context of the PaperCut server process.

At a glance

Exploited
Yes: on CISA's Known Exploited list
Severity
9.4 Critical (CVSS 4.0)
Chance of exploitation
60.9% in the next 30 days
CISA federal deadline
Sep 14, 2026: passed
Sources
2 independent sources

What 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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Read CISA KEV entry CVE-2026-82078 (opens a new tab)

What happened

PaperCut NG/MF contains an unsafe reflection vulnerability that allows an attacker to manipulate system configuration parameters and execute arbitrary Java bytecode residing on the application classpath under the security context of the PaperCut server process. This vulnerability can be chained with CVE-2026-81578.

CISA federal deadline

Federal due date passed

Applies to covered US federal agencies; it is not your organization's deadline.

Added to the catalog Known ransomware use: Unknown
CISA catalog (opens a new tab)

Scores and how they were measured

CVSS base severity

9.4

Version 4.0As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

60.9%

Scored Percentile 99.1%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    CISA KEV entry CVE-2026-82078 (opens a new tab)

    The CVE-2026-82078 catalog entry establishes known exploitation, date added, required action, and the federal due date; not zero-day status.

    Published Checked

  2. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-82078, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

  3. Primary source

    CVE Program CNA PaperCut (opens a new tab)

    The published CVE-2026-82078 document's CNA supplies this CVSS 4.0 base score, vector, and authoritative source update date.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, August 31). PaperCut NG/MF Unsafe Reflection Vulnerability (CVE-2026-82078). https://kevwire.com/record/CVE-2026-82078

MLA

"PaperCut NG/MF Unsafe Reflection Vulnerability (CVE-2026-82078)." KEVWire, 31 Aug. 2026, kevwire.com/record/CVE-2026-82078.

Chicago

KEVWire. "PaperCut NG/MF Unsafe Reflection Vulnerability (CVE-2026-82078)." Last modified August 31, 2026. https://kevwire.com/record/CVE-2026-82078.

Evidence summary (plain text)

PaperCut NG/MF Unsafe Reflection Vulnerability (Aug 31, 2026).
PaperCut NG/MF contains an unsafe reflection vulnerability that allows an attacker to manipulate system configuration parameters and execute arbitrary Java bytecode residing on the application classpath under the security context of the PaperCut server process. This vulnerability can be chained with CVE-2026-81578.
CVSS 9.4 (version 4.0; evidence as of Sep 13, 2026; https://cveawg.mitre.org/api/cve/CVE-2026-82078).
EPSS 60.9% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-82078&date=2026-10-26).
Sources:
CISA KEV entry CVE-2026-82078: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-82078&date=2026-10-26
CVE Program CNA PaperCut: https://cveawg.mitre.org/api/cve/CVE-2026-82078
Record ID: CVE-2026-82078.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Documented by a cited source.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
CISA federal due date: Sep 14, 2026. This is a deadline for covered US federal agencies, not the reader's SLA.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

CISA added this entry on 2026-08-31. This record's publication date is the catalog addition date, not necessarily the initial vulnerability disclosure. KEV means known exploitation, not necessarily a zero-day. CISA due dates apply to covered US federal agencies, not your organizational SLA.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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