CVE-2023-27351

Improper Authentication

CVSS 3.0 High 8.2Known exploited (CISA KEV)

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

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.

Key data

CVSS 3.0 High 8.2

Score published by zdi in the CVE record.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Attack vector: Network
The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity: Low
No special conditions are needed. The attack can be repeated at will.
Privileges required: None
No account or privileges are needed.
User interaction: None
No action from any user is needed.
Scope: Unchanged
The impact stays within the vulnerable component.
Confidentiality impact: High
Serious or total effect on the secrecy of data.
Integrity impact: Low
Limited effect on the trustworthiness of data.
Availability impact: None
No effect on availability.

Metric	Value	What it means
Attack vector	Network	The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity	Low	No special conditions are needed. The attack can be repeated at will.
Privileges required	None	No account or privileges are needed.
User interaction	None	No action from any user is needed.
Scope	Unchanged	The impact stays within the vulnerable component.
Confidentiality impact	High	Serious or total effect on the secrecy of data.
Integrity impact	Low	Limited effect on the trustworthiness of data.
Availability impact	None	No effect on availability.

CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at first.org/cvss.

EPSS

Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days.

Score: 0.78052 (78.1% probability)
Percentile: 99.6%
Scores of: Nov 10, 2026
Model: v2026.06.15

CISA Known Exploited Vulnerabilities

This CVE is listed in the CISA KEV catalog.

Name in the catalog: PaperCut NG/MF Improper Authentication Vulnerability
Added to the catalog: Apr 20, 2026
Federal due date: May 4, 2026
Ransomware campaigns: Known use

CISA assessment as of Apr 21, 2026

Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA.

Exploitation: Recorded by CISA as active
Automatable: yes
Technical impact: total

Weakness (CWE)

CWE catalog version 5.0.

CWE-287Improper Authentication

Affected products

Products listed in the CVE record, as the CNA published them.

PaperCut NG
- affected: 22.0.5 (Build 63914)

References

Links listed in the CVE record. They lead to other sites, which CubePath does not control.

Timeline

ID reservedFeb 28, 2023
Record publishedApr 20, 2023
Added to CISA KEVApr 20, 2026
Record last updatedOct 1, 2026

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About CubePath

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Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:10 UTC. Sources and licenses