# CVE-2023-27351: PaperCut NG/MF Improper Authentication Vulnerability

> CVE-2023-27351: PaperCut NG/MF Improper Authentication Vulnerability. CVSS 8.2 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2023-27351
Last updated: 2026-10-01T19:17:14Z

- Published: 2023-04-20 00:00 UTC · Updated: 2026-10-01 19:17 UTC · Assigner: zdi
- CVSS: 8.2 (CVSS 3.1) · Severity: High · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- EPSS: 78.1%, 100th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2026-04-20, federal due date 2026-05-04, ransomware use: Known
- CWE: CWE-287

## Description

This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.

## CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

## Affected vendors and products

- PaperCut: NG

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2023-27351)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2023-27351)
- [https://www.papercut.com/kb/Main/PO-1216-and-PO-1219](https://www.papercut.com/kb/Main/PO-1216-and-PO-1219)
- [https://www.zerodayinitiative.com/advisories/ZDI-23-232/](https://www.zerodayinitiative.com/advisories/ZDI-23-232/)

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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-2023-27351 · Markdown: https://rewindex.com/cve/CVE-2023-27351.md · JSON: https://rewindex.com/api/v1/cves/CVE-2023-27351 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:04:41.148Z