CVE-2026-81578
PaperCut MF/NG
Published 28 Aug 2026 · updated 14 Sept 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 31 Aug 2026, with a remediation deadline of 14 Sept 2026 for US federal agencies.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
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.
References
- www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ · Patch, Vendor Advisory
- github.com/rapid7/metasploit-framework/pull/21842 · Issue Tracking, Patch
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578 · Patch, Third Party Advisory, US Government Resource