CVE-2023-27351

HIGH

7.5

CVSS Score

Published: April 20, 2023 at 12:00 AM UTC

Updated: October 1, 2026 at 07:17 PM UTC

2 products affected across 1 vendorPapercut NgPaperCut MF

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Severity

HIGH7.5

Exploitation

CISA KEV

Exploit prediction

EPSS 78%

SSVC

Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score78.1%

EPSS (Exploit Prediction Scoring System) estimates a 78.1% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.

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 Use

Known

Added to KEV

Apr 20, 2026

Remediation Due

May 4, 2026

181 days overdue

Notes

https://www.papercut.com/kb/Main/PO-1216-and-PO-1219

https://nvd.nist.gov/vuln/detail/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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

PaperCut MF · Papercut

95%

15.0 ≤ v < 20.1.721.0.0 ≤ v < 21.2.1122.0.0 ≤ v < 22.0.9

Affected range stops below 20.1.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.2.11, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.0.9, so it looks safe — our inference, not a vendor statement

Papercut Ng · Papercut

95%

15.0 ≤ v < 20.1.721.0.0 ≤ v < 21.2.1122.0.0 ≤ v < 22.0.922.0.5 (Build 63914)

Affected range stops below 20.1.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.2.11, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.0.9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://www.papercut.com/kb/Main/PO-1216-and-PO-1219

References (3)

Vendor Advisory

Source: [email protected]

https://www.papercut.com/kb/Main/PO-1216-and-PO-1219

Third Party AdvisoryVDB Entry

Source: [email protected]

https://www.zerodayinitiative.com/advisories/ZDI-23-232/

US Government Resource

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27351

SSVC — Action Prioritization

SSVCActiveAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: NONE
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-287

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