Impact Trying to read malformed HAMT sharded directories can cause panics and virtual memory leaks. If you are reading untrusted user input, an attacker can then trigger a panic.

This is caused by bogus fanout parameter in the HAMT directory nodes. This include checks returned in ipfs/go-bitfield GHSA-2h6c-j3gf-xp9r, as well as limiting the fanout to <= 1024 (to avoid attempts of arbitrary sized allocations).

Patches - https://github.com/ipfs/go-unixfs/commit/dbcc43ec3e2db0d01e8d80c55040bba3cf22cb4b

Workarounds Do not feed untrusted user data to the decoding functions.

References - https://github.com/ipfs/go-bitfield/security/advisories/GHSA-2h6c-j3gf-xp9r