GHSA-5FQC-MRG8-W798 Dulwich: Symlink directory traversal in filter-branch index_filter via cross-commit state persistence

Summary Dulwich's filterbranch.py CommitFilter.applyindexfilter is vulnerable to symlink directory traversal. When processing commit history, materialized tree entries including symlinks persist in the working directory between commits, allowing a symlink from an ancestor commit to redirect file...