What happened
CISA added CVE-2026-82078 affecting PaperCut NG/MF to its Known Exploited Vulnerabilities catalog on August 31, 2026.
CISA vulnerability name: PaperCut NG/MF Unsafe Reflection Vulnerability
PaperCut NG/MF contains an unsafe reflection vulnerability that allows an attacker to manipulate system configuration parameters and execute arbitrary Java bytecode residing on the application classpath under the security context of the PaperCut server process. This vulnerability can be chained with CVE-2026-81578.
Why it matters
Inclusion in CISA’s KEV catalog means the vulnerability has met CISA’s criteria for known exploitation in the wild. That makes it a higher-priority remediation signal than a vulnerability that is only theoretically exploitable.
CWE: CWE-470
What you should do
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.
CISA remediation due date for federal civilian agencies: September 14, 2026.
Additional CISA notes
https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/?lid=2oneu2wt0ct4 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-82078