CVEvulnerability

CVE-2026-81578

8.8 HIGH Known exploited Published 2026-08-28 Modified 2026-09-14 Official page ↗

CISA Known Exploited Vulnerability

PaperCut NG/MF Missing Authentication for Critical Function Vulnerability — PaperCut NG/MF

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.

Added to KEV: 2026-08-31
Remediation due: 2026-09-14
Ransomware use: Unknown
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.
Notes: https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-81578

Status: Analyzed
Published: 2026-08-28
Last modified: 2026-09-14
Assigner: eb41dac7-0af8-4f84-9f6d-0272772514f4
CVSS 4.0 (eb41dac7-0af8-4f84-9f6d-0272772514f4): 8.8 HIGH — 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
CVSS 3.1 ([email protected]): 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses: CWE-305

Description

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 configurations

• papercut papercut mf (< 24.1.9) • papercut papercut mf (>= 25.0.2 < 25.0.12) • papercut papercut mf (>= 26.0.2 < 26.0.4) • papercut papercut ng (< 24.1.9) • papercut papercut ng (>= 25.0.2 < 25.0.12) • papercut papercut ng (>= 26.0.2 < 26.0.4)

Weakness · CWE (1)

CWE-305 Authentication Bypass by Primary Weakness weakness

References