AIKIDO-2026-281672

TL;DR

Dulwich parses packs and loose objects from repository data without bounding the work implied by attacker-controlled headers. zlib decompression of pack entries and loose objects is not capped against the declared inflated size, so a decompression-bomb object can exhaust process memory, and an OFS_DELTA pack entry whose delta_base_offset is zero references itself so Pack.resolve_object loops forever growing its delta stack until the process runs out of memory. Processing a crafted pack or loose object from an untrusted repository can therefore hang the process or exhaust memory. The fix caps zlib decompression at the declared size, plumbs a core.bigFileThreshold-based limit into loose-object parsing, and rejects OFS_DELTA entries whose base offset is zero.