CVE-2026-81578

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Media report

EPSS 0.39%
Published 28.08.2026 11:39:45
Last modified 14.09.2026 00:16:56
Findings
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PaperCut MF/NG: Authentication Bypass

An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the  completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.

Affected products Warnings 1 Metrics 3 CWE 1 References 15

NVD 6 VulnDex Vulnerability Enrichment 2

Data is provided by the National Vulnerability Database (NVD)

Papercut ≫ Papercut Mf Version < 24.1.9

Papercut ≫ Papercut Mf Version >= 25.0.2 < 25.0.12

Papercut ≫ Papercut Mf Version >= 26.0.2 < 26.0.4

Papercut ≫ Papercut Ng Version < 24.1.9

Papercut ≫ Papercut Ng Version >= 25.0.2 < 25.0.12

Papercut ≫ Papercut Ng Version >= 26.0.2 < 26.0.4

VulnDex Vulnerability Enrichment

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28.08.2026: CISA Known Exploited Vulnerabilities (KEV) Catalog

PaperCut NG/MF Missing Authentication for Critical Function Vulnerability

Vulnerability

PaperCut NG/MF contains a missing authentication for critical function vulnerability which allows an unauthenticated remote attacker to modify certain system configurations. This vulnerability can be chained with CVE-2026-82078.

Description

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.

Required actions

EPSS Metrics
Type	Source	Score	Percentile
EPSS	FIRST.org	0.39%	0.323

CVSS Metrics
Source	Base Score	Exploit Score	Impact Score	Vector string
NIST	9.8	3.9	5.9	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
eb41dac7-0af8-4f84-9f6d-0272772514f4	8.8	0	0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N/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

CWE-305 Authentication Bypass by Primary Weakness

The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.