CVE-2023-27351
PaperCut NG
Published 20 Apr 2023 · updated 1 Oct 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 20 Apr 2026, with a remediation deadline of 4 May 2026 for US federal agencies. It has been used in ransomware campaigns.
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.
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.
References
- www.papercut.com/kb/Main/PO-1216-and-PO-1219 · Vendor Advisory
- www.zerodayinitiative.com/advisories/ZDI-23-232/ · Third Party Advisory, VDB Entry
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27351 · US Government Resource