CVE-2023-27351 PaperCut NG/MF Improper Authentication

Exploited in the wild High 8.2 Published 20 Apr 2023 Updated 1 Oct 2026

Remote attackers can bypass authentication in PaperCut NG due to a flaw in the SecurityRequestFilter, allowing unauthorized system access.

Exploited in the wild: Since 20 Apr 2026
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-27351?

CVE-2023-27351 is a high-severity authentication bypass vulnerability in PaperCut NG, published on 20 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-287

Which versions are affected by CVE-2023-27351?

It affects 2 products.

Products include Papercut Papercut Mf, Papercut Papercut Ng.

How do I fix CVE-2023-27351?

No fix has been published for CVE-2023-27351 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 4 May 2026.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2023-27351 being exploited?

Yes. Attackers have exploited CVE-2023-27351 in the wild since at least 20 Apr 2026, including in ransomware campaigns.

Public exploit code: 1 Nuclei template.

Sources

Also known as GHSA-2c69-r2jh-xjvm.