MSRXCVE-2026-81578
CVE-2026-81578
PaperCut NG/MF Missing Authentication for Critical Function Vulnerability
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.
CVSS 4.0 · CNA
chance of exploitation in the next 30 days (EPSS; in the top 1% of all CVEs)
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.
Scores
Affected products
- papercut papercut mf: < 24.1.9; ≥ 25.0.2, < 25.0.12; ≥ 26.0.2, < 26.0.4
- papercut papercut ng: < 24.1.9; ≥ 25.0.2, < 25.0.12; ≥ 26.0.2, < 26.0.4
Weakness: CWE-305
3 references (advisories, patches, write-ups)
- https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ · Patch, Vendor Advisory
- https://github.com/rapid7/metasploit-framework/pull/21842 · Issue Tracking, Patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578 · Patch, Third Party Advisory, US Government Resource
Sources: NVD, CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.