Authentication Bypass Risk in PaperCut NG/MF Print Management

Historical catalog analysis: CISA added this entry on April 20, 2026. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2023-27351 is an improper authentication vulnerability (CWE-287) affecting PaperCut NG/MF software. The flaw exists within the SecurityRequestFilter class, which could allow a remote attacker to bypass authentication mechanisms on affected installations. According to CISA, this vulnerability is known to be utilized in ransomware campaigns.

Exposure and applicability

Print management systems are frequently deployed across U.S. healthcare facilities to handle administrative documentation and the processing of patient records. Because these systems often interface with sensitive data streams, an authentication bypass could provide unauthorized actors with a foothold in the network or access to electronic Protected Health Information (ePHI) handled by the print server.

This vulnerability is particularly relevant for healthcare security leaders and clinical engineering teams managing on-premises or cloud-based print infrastructure. The risk is elevated given the reported use of this flaw by ransomware operators, which could threaten both data confidentiality and the continuity of patient care if print services are disrupted or used as an entry point for broader network encryption.

Remediation priorities

Based on our analysis of the vulnerability, healthcare organizations should prioritize the following actions to reduce their risk profile:

1. Immediate Patching/Mitigation: Apply vendor-supplied mitigations and updates specifically addressing CVE-2023-27351. This is the primary control for preventing initial unauthorized access via this flaw.
2. Cloud Service Review: For organizations utilizing cloud-based deployments, review configurations against current guidance (such as BOD 22-01) to ensure authentication filters are correctly implemented.
3. Infrastructure Assessment: Identify all instances of PaperCut NG/MF across the clinical and administrative environment to ensure no legacy or shadow IT servers remain unpatched.
4. Decommissioning: If mitigations cannot be applied or are unavailable for a specific version in use, our analysis suggests discontinuing the use of the product to eliminate the attack vector.

How to validate remediation

To verify that exposure has been reduced, security teams should coordinate with IT and clinical engineering to perform the following:

• Version Verification: Confirm that the installed software version matches the vendor’s patched or mitigated release. Note that a version check alone does not guarantee total security but confirms the application of the fix.
• Configuration Audit: Review system logs for unauthorized access attempts targeting the SecurityRequestFilter class prior to and after patching.
• Access Control Validation: Verify through authorized administrative audits that authentication is required for all management interfaces and that bypass attempts are rejected.

Limits and open questions

Applying vendor mitigations could reduce the likelihood of exploitation, but it does not guarantee complete immunity from all ransomware risks. There remains a residual risk if other vulnerabilities exist within the environment or if credentials were compromised prior to patching.

It is currently unknown exactly how many healthcare entities have been targeted via this specific vector. Organizations should also determine if their specific deployment architecture (e.g., integrated with medical device printing) introduces unique dependencies that require vendor-specific coordination before applying updates.

Source and editorial note

CVE-2023-27351: PaperCut NG/MF Improper Authentication Vulnerability · Source date: April 20, 2026 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: April 23, 2026. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: September 11, 2026 at 01:30 UTC.

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