Vulnerability · CVE-2023-27351
PaperCut NG/MF Improper Authentication Vulnerability
Published Apr 20, 2023 · catalog updated Oct 1, 2026 · PaperCut NG/MF
Patch now
CVE-2023-27351 is in the CISA known-exploited catalog, due May 4, 2026. Confirm PaperCut NG/MF against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Gaps on this record
- No version range is stored. A customer cannot check an installed version against this record.
- Severity
- High7.5
- Known exploitation
- CISA KEV and VulnCheck KEV
- EPSS
- 78.05%
- Remediation
- Remediation guidance
- Affected products
- cpe papercut/papercut mf · cpe papercut/papercut ng · vendor PaperCut NG/MF
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe papercut/papercut mfversion unspecified
- cpe papercut/papercut ngversion unspecified
- vendor PaperCut NG/MFversion unspecified
How to fix CVE-2023-27351
Recommended remediation
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. CISA due date May 4, 2026.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
CVE-2023-27351 is in the CISA known-exploited catalog, due May 4, 2026. Confirm PaperCut NG/MF against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Which versions are affected?
Affected version ranges are not on this record. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
What should an analyst verify?
CWE-287: Improper Authentication. EPSS 78.05%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Apr 20, 2023 · Catalog
Detected
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 authenti
Apr 20, 2026 · CISA KEV
Known exploited
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
May 4, 2026 · CISA KEV
Remediation due
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Oct 1, 2026 · Catalog
Updated
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 authenti
Sources
- CISA KEVConfirmed exploitationCVE-2023-27351
PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.
cisa.gov - CVE.orgVulnerability recordCVE-2023-27351
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2023-27351
30-day exploitation probability 78.1%
first.org - NIST NVDVulnerability recordCVE-2023-27351
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
nvd.nist.gov - VulnCheck KEVConfirmed exploitationCVE-2023-27351
PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.
vulncheck.com
References
- VulnCheck exploitation evidence · 4502402.fs1.hubspotusercontent-na1.net
- VulnCheck exploitation evidence · blog.sekoia.io
- VulnCheck exploitation evidence · go.recordedfuture.com
- CISA note · nvd.nist.gov
- US Government Resource · cisa.gov
- VulnCheck exploitation evidence · hhs.gov
- VulnCheck exploitation evidence · hhs.gov
- CISA note · papercut.com
- VulnCheck exploitation evidence · sentinelone.com
- Third Party Advisory · zerodayinitiative.com
Freshness
Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.