PYSEC-2026-2617 Mako vulnerable to path traversal via backslash URI on Windows in TemplateLookup

Summary On Windows, a URI using backslash traversal e.g. ....\ secret.txt bypasses the directory traversal check in Template.init and the posixpath-based normalization in TemplateLookup.gettemplate, allowing reads of files outside the configured template directory. Details The root cause is a...