CVE-2023-27351

Q: How do I fix CVE-2023-27351?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Q: Is CVE-2023-27351 being actively exploited?

Yes. CVE-2023-27351 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. CISA has also linked it to known ransomware campaigns. US federal agencies were required to remediate it by 2026-05-04. Treat it as a priority whatever its CVSS score says.

Q: How severe is CVE-2023-27351?

CVE-2023-27351 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2023-27351 affect?

Published advisories record a fix for papercut mf (NVD), papercut ng (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

HIGHCISA KEVEPSS 100th pctl

7.5

CVSS v3

NVD

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.

CWE-287Improper Authentication

How to fix

Remediation Available

papercut mfNVD

Affected:>= 22.0.0, < 22.0.9Fixed in:22.0.9CVE-2023-27351derived from NVD

papercut ngNVD

Affected:>= 22.0.0, < 22.0.9Fixed in:22.0.9CVE-2023-27351derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploit Intelligence

77.39%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Remediation due: 2026-05-04

Associated with ransomware campaigns

References

Vendor Advisory1

papercut.com

Third-Party Advisory1

zerodayinitiative.com

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-35082	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-35078	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2017-7921	Critical	9.8	100%	KEV	-
CVE-2024-7593	Critical	9.8	100%	KEV	-
CVE-2023-46805	High	8.2	100%	KEV + Ransom	-
CVE-2022-40684	Critical	9.8	100%	KEV + Ransom	Fix

Common questions

How do I fix CVE-2023-27351?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2023-27351 being actively exploited?

Yes. CVE-2023-27351 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. CISA has also linked it to known ransomware campaigns. US federal agencies were required to remediate it by 2026-05-04. Treat it as a priority whatever its CVSS score says.

How severe is CVE-2023-27351?

CVE-2023-27351 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2023-27351 affect?

Published advisories record a fix for papercut mf (NVD), papercut ng (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.