What is CVE-2026-81578?
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.
Timeline
- 2026-08-28Published to the U.S. National Vulnerability Database (NVD)
- 2026-08-31Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
- 2026-09-02First covered in a defend.network daily briefing
- 2026-09-14CISA federal remediation deadline (BOD 22-01)
- 2026-09-14NVD record last updated
CISA Known Exploited Vulnerability
PaperCut NG/MF Missing Authentication for Critical Function Vulnerability
Affected product
PaperCut NG/MF
NVD also lists CPE entries for: Papercut Mf, Papercut Ng
Remediation Steps
- Apply the vendor patch to address the authentication bypass flaw
- Review access logs for evidence of unauthorized authentication or command execution
- Conduct credential audit of accounts that may have been exposed
- Restrict network access to PaperCut management interfaces
References
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578
- https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/
- https://github.com/rapid7/metasploit-framework/pull/21842
- https://nvd.nist.gov/vuln/detail/CVE-2026-81578
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Referenced in our briefings & reports
- Vulnerability Priority Report – Week 4 of September 2026 (September 28 – October 4)
- Vulnerability Priority Report – Week 3 of September 2026 (September 21 – 27)
- Vulnerability Priority Report – Week 2 of September 2026 (September 14 – 20)
- Vulnerability Priority Report – Week 1 of September 2026 (September 7 – 13)
- Vulnerability Priority Report – Week 5 of August 2026 (August 31 – September 6)
- JFrog Artifactory, Langflow critical flaws exploited; TeamPCP arrested (2026-09-02)
Browse all tracked CVEs in the defend.network CVE database →
🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.