CVE-2026-81578
CriticalPaperCut NG/MF Missing Authentication for Critical Function Vulnerability
9.8 CVSS v3.1
CVSS v4.0: 8.8
- Published
- Aug 28, 2026
- Updated
- Sep 14, 2026
- Vendor
- Papercut
- Affected versions
- See affected products
- Weakness
- CWE-305
Summary
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.
Severity
Critical (9.8)CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0 (8.8)
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
Affected products
- 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
Exploitation status
Actively exploited
Listed in the CISA Known Exploited Vulnerabilities catalog on Aug 31, 2026. Federal remediation due: Sep 14, 2026.
Technical details
Technical analysis has not been written for this record yet.
Mitigation & remediation
- 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.