CVE-2026-81578: PaperCut MF/NG: Authentication Bypass
In CISA’s Known Exploited Vulnerabilities catalog: PaperCut NG/MF Missing Authentication for Critical Function Vulnerability.
Added , federal remediation due . Known 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.
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.
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H · CWE-305
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
PaperCut: PaperCut MF/NG
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)