CVE-2026-81578 PaperCut NG/MF Missing Authentication for Critical Function

Exploited in the wild High 8.8 Published 28 Aug 2026 Updated 13 Sep 2026

Unauthenticated attackers can bypass access controls to modify system configurations in PaperCut MF/NG web interfaces.

Exploited in the wild: Since 31 Aug 2026
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-81578?

CVE-2026-81578 is a high-severity authentication bypass vulnerability in PaperCut MF/NG, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.

Weakness: CWE-305

Which versions are affected by CVE-2026-81578?

It affects 2 products.

Products include Papercut Papercut Mf, Papercut Papercut Ng.

How do I fix CVE-2026-81578?

No fix has been published for CVE-2026-81578 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 14 Sep 2026.

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

Is CVE-2026-81578 being exploited?

Yes. Attackers have exploited CVE-2026-81578 in the wild since at least 31 Aug 2026.

Public exploit code: 1 Metasploit module, 1 Nuclei template and 2 proofs of concept on GitHub.

Sources

Also known as GHSA-44wc-j6f2-7fjr.