Safari 11.0.3
Apple has released Safari 11.0.3 for OS X 10.11.6 El Capitan and macOS 10.12.6 Sierra. OS X (High Sierra 10.13.3 also includes it; see “Apple Releases iOS 11.2.5, macOS 10.13.3, watchOS 4.2.2, and tvOS 11.2.5,” 23 January 2018). The update improves memory handling to resolve multiple memory corruption issues that could lead to arbitrary code execution when processing a maliciously crafted Web page. Safari 11.0.3 is available only via Software Update. (Free, release notes, 10.11.6+)