CVE-2018-4878

CVE-2018-4878 is a use-after-free (CWE-416) in Adobe Flash Player before 28.0.0.161, caused by a dangling pointer in the Primetime SDK's media-player handling of listener objects. An attacker triggers it by persuading a user to open attacker-controlled Flash content — typically a malicious SWF delivered via email, Office documents, or malvertising/exploit kits — because the CVSS vector (AV:L, UI:R) requires local user interaction. Successful exploitation yields arbitrary code execution with the privileges of the user running Flash. Anyone running a vulnerable Flash Player was exposed, including Red Hat Enterprise Linux Desktop/Server/Workstation users running Red Hat's packaged Flash plugin. The flaw was exploited as a zero-day in January–February 2018 (documented by McAfee and distributed alongside the Fallout exploit kit), and it remains in CISA's KEV with known ransomware use.

What to do: Upgrade Adobe Flash Player to 28.0.0.161 or later, including Red Hat's flash-plugin package on RHEL Desktop/Server/Workstation. Because Flash is now end-of-life, CISA's required KEV action is to remove or disconnect Flash entirely where still in use — audit browsers, Office configurations, and legacy RHEL hosts for residual Flash installs, and block SWF content delivered via email and the web. Given confirmed in-the-wild exploitation, known ransomware use, and 89.5% EPSS, prioritize this in remediation tracking.