CVE-2026-81578: listed in the CISA KEV catalog

CVE-2026-81578 · KEV 2026-08-28 · patch available

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.

Is CVE-2026-81578 exploited?

• Listed in the CISA KEV catalog on 2026-08-28.
• Federal remediation due 2026-09-11.
• Past that date by 48 days.
• Public exploit code: packaged in a public tool.
• Public detection rules exist.

Which products and versions are affected?

• PaperCut · PaperCut MF/NG · >= 0, < 24.1.10, >= 25.0.0, < 25.0.13, >= 26.0.0, < 26.0.5

Is there a patch?

Yes. Update to one of these or later:

From PaperCut's CVE record · PaperCut advisory

What PlainSec published about CVE-2026-81578

• PaperCut exploitation stays open after advisory (2026-10-12)
• PaperCut zero-days shift from access to theft (2026-09-02)
• PaperCut’s exploit chain splits into two CVEs (2026-09-01)

Primary sources

• NVD record
• CISA KEV catalog
• PaperCut advisory
• Metasploit: exploit/multi/http/papercut_ng_external_user_lookup_rce
• Nuclei template

What this record does not say

• No CVSS score from NVD.
• No EPSS score.

KEV and EPSS are re-checked daily. Record last updated 2026-10-09.