High severity · published Apr 20, 2023
CVE-2023-27351
PaperCut NG/MF Improper Authentication Vulnerability
RansomwareIn wildKEV
7.5
CVSS
78.1%
EPSS
Yes
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)78.1% · higher than 100% of CVEs
Exploited in the wildYes
CISA KEVListed Apr 20, 2026
Federal remediation dueMay 4, 2026
Ransomware campaign useKnown
Affected products
Which versions
PM
PaperCut MF/NG · PaperCut
22.0.5 (Build 63914) · source: vendor, NVD
NG
NG/MF · PaperCut
All versions, or not specified · source: KEV
In the news
AdvisoryHigh
CISA Adds Eight Known Exploited Vulnerabilities to Catalog
CISA has added eight new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation.
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CVE-2026-20128 Cisco Catalyst SD-WAN Manager Storing Passwords in a Recoverable Format Vulnerability
CVE-2026-20133 Cisco Catalyst SD-WAN Manager Exposure of Sensitive Information to an Unauthorized Actor Vulnerability
These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise.
Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Branch (FCEB) agencies to remediate identified vulnerabilities by the due date to protect FCEB networks against active threats. Se...
Apr 20, 2026·CISA Advisories
VulnerabilityHigh
[CISA KEV] CVE-2023-27351: PaperCut NG/MF - PaperCut NG/MF Improper Authentication Vulnerability
PaperCut NG/MF contains an improper authentication vulnerability that could allow remote attackers to bypass authentication on affected installations via the SecurityRequestFilter class.
NGNG/MFCVE-2023-27351
Apr 20, 2026·CISA KEV
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-27351
CVE.org
https://www.cve.org/CVERecord?id=CVE-2023-27351
CISA KEV catalogue
https://www.cisa.gov/known-exploited-vulnerabilities-catalog
www.papercut.com
https://www.papercut.com/kb/Main/PO-1216-and-PO-1219
www.zerodayinitiative.com
https://www.zerodayinitiative.com/advisories/ZDI-23-232/
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