horizon3.ai • 5m
PaperCut NG/MF: Critical Authentication Bypass and RCE Chain CVE-2026-81578 & CVE-2026-82078
PaperCut NG and MF are subject to an active zero-day exploit chain combining an authentication bypass (CVE-2026-81578) and unsafe dynamic class loading (CVE-2026-82078). Attackers leverage the Apache Tapestry framework's 'complex direct' request format to mask administrative calls, bypassing access controls to modify external user-lookup database settings. By injecting malicious JDBC connection strings utilizing Apache Derby's 'foreignViews' and the H2 database's 'INIT' statement, attackers trigger the Nashorn JavaScript engine to achieve unauthenticated Remote Code Execution (RCE) via the pc-app.exe process. Immediate application of the second version of the emergency patch is mandatory to mitigate the risk of full system compromise.