# CVE-2026-81578: PaperCut MF/NG: Authentication Bypass

> CVE-2026-81578: PaperCut MF/NG: Authentication Bypass. CVSS 9.8 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2026-81578
Last updated: 2026-09-14T00:16:56Z

- Published: 2026-08-28 11:39 UTC · Updated: 2026-09-14 00:16 UTC · Assigner: PaperCut
- CVSS: 9.8 (CVSS 3.1) · Severity: Critical · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS: 83.7%, 100th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2026-08-31, federal due date 2026-09-14, ransomware use: Unknown
- CWE: 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.

## CISA 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.

## Affected vendors and products

- PaperCut: PaperCut MF/NG

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-81578)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-81578)
- [https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/](https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-81578 · Markdown: https://rewindex.com/cve/CVE-2026-81578.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-81578 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:13:42.947Z