CVE-2023-27351

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.

Overview

State: PUBLISHED
Assigner (CNA): zdi
CVSS severity: HIGH
CVSS score: 8.2 / 10
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Effective score: 8.2 / 10 HIGH source: CNA overview
CWE(s): CWE-287
Reserved: 2023-02-28
Published: 2023-04-20 00:00 UTC
Last updated: 2026-04-21 03:55 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2023/27xxx/CVE-2023-27351.json
Linked Threat: CVE-2023-27351 — PaperCut NG/MF: PaperCut NG/MF Improper Authentication Vulnerability

CISA Known Exploited Vulnerabilities CISA KEV

CISA has confirmed in-the-wild exploitation of this CVE. Federal agencies must remediate by the due date below; private orgs should treat it as priority-1.

Vulnerability name: PaperCut NG/MF Improper Authentication Vulnerability
Vendor / project: PaperCut
Product: NG/MF
Date added to KEV: 2026-04-20
Remediation due: 2026-05-04
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.
Ransomware campaign use: Known
CISA notes: https://www.papercut.com/kb/Main/PO-1216-and-PO-1219 ; https://nvd.nist.gov/vuln/detail/CVE-2023-27351
CISA listing: www.cisa.gov/known-exploited-vulnerabilities-catalog

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2023-04-20 16:15:07 UTC
NVD last modified: 2026-04-21 13:00:03 UTC
NVD CVSS v3.1: 7.5 / 10 HIGH source: nvd@nist.gov
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploitability subscore: 3.9 / 10
Impact subscore: 3.6 / 10
EPSS score: 0.8328 (probability of exploitation in next 30 days)
EPSS percentile: 99.28% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2023-31127
Assigner: zdi
Published: Apr 20, 2023, 12:00:00 AM
Updated: Apr 21, 2026, 3:55:37 AM
EUVD base score (CVSS 3.0): 8.2 / 10
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
EUVD-reported EPSS: 83.2800
Vendors: PaperCut
Products: NG (22.0.5 (Build 63914))
Aliases: GHSA-2c69-r2jh-xjvm

ENISA 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.

EUVD references (2)

Affected products (1)

Vendor	Product	Versions	Platforms
PaperCut	NG	`22.0.5 (Build 63914)` (affected)	—

Affected products — CPE 2.3 (2) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

Web references (6)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

http://cwe.mitre.org/data/definitions/287.html rapid7:cwe.mitre.org
https://attackerkb.com/topics/CVE-2023-27351 rapid7:attackerkb.com
https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-31127 rapid7:euvd.enisa.europa.eu
https://www.cve.org/CVERecord?id=CVE-2023-27351 rapid7:www.cve.org
https://www.papercut.com/kb/Main/PO-1216-and-PO-1219 rapid7:www.papercut.com
https://www.zerodayinitiative.com/advisories/ZDI-23-232/ rapid7:www.zerodayinitiative.com

NVD-tagged references (5)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27351 134c704f-9b21-4f2e-91b3-4a467353bcc0 US Government Resource
https://www.papercut.com/kb/Main/PO-1216-and-PO-1219 zdi-disclosures@trendmicro.com Vendor Advisory
https://www.papercut.com/kb/Main/PO-1216-and-PO-1219 af854a3a-2127-422b-91ae-364da2661108 Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-23-232/ zdi-disclosures@trendmicro.com Third Party AdvisoryVDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-23-232/ af854a3a-2127-422b-91ae-364da2661108 Third Party AdvisoryVDB Entry

Indicators (2)

IOCs linked to the auto-promoted Threat row.

Type	Value	VirusTotal	Attached
cve	`CVE-2023-27351`	no local data	2026-05-14 02:58 UTC
cwe	`CWE-287`	no local data	2026-05-14 02:58 UTC

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Rapid7 — Solution

rapid7

papercut-march-2023-upgrade-to-recommended-version

2026-05-28 23:31 UTC
Microsoft Patch Tuesday May 2026 - 120 Vulnerabilities Fixed, Including ...

web:cybersecuritynews.com

Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.

2026-05-14 08:18 UTC
Nvd - Cve-2023-27351

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-14 08:18 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-14 08:18 UTC
Microsoft's May 2026 Patch Tuesday Fixes 130+ Vulnerabilities ...

web:windowsreport.com

Microsoft has released its May 2026 Patch Tuesday updates for Windows 11 and Windows 10, shipping as KB5089549 and KB5087544. The updates include fixes for more than 130 security vulnerabilities across Windows, Office, SharePoint, DNS components, and core system services, as Bleeping Computer writes.

2026-05-14 08:18 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-14 08:18 UTC
CVE Record: CVE-2023-27351

web:www.cve.org

Vulnerability detail for CVE-2023-27351 Notice: Expanded keyword searching of CVE Records (with limitations) is now available in the search box above. Learn more here.

2026-05-14 08:18 UTC
Microsoft May 2026 Patch Tuesday Fixes 130+ Vulnerabilities ... - LinkedIn

web:www.linkedin.com

Microsoft has released its May 2026 Patch Tuesday security updates, addressing more than 130 vulnerabilities across its software ecosystem, including Windows, Microsoft Office, SharePoint Server ...

2026-05-14 08:18 UTC
CVE-2023-27351: PaperCut MF Auth Bypass Vulnerability - SentinelOne

web:www.sentinelone.com

CVE-2023-27351 is an authentication bypass vulnerability in PaperCut MF. Learn about its impact, affected versions, and mitigation methods.

2026-05-14 08:18 UTC
CISA Required Action

CISA KEV

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Due date: 2026-05-04 Known ransomware campaign use: Known

2026-05-14 01:13 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2023-27351.json.

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