go-ipld-prime's DAG-CBOR and DAG-JSON decoders have unbounded recursion depth

The DAG-CBOR and DAG-JSON decoders recurse on each nested map or list without a depth limit. A payload containing deeply nested collections causes the decoder to recurse once per level, growing the goroutine stack until the Go runtime terminates the process with a fatal stack overflow (distinct from a recoverable panic). For DAG-CBOR, a payload of approximately 2 MB, consisting of repeated `0x81` (array-of-1) bytes followed by a terminator, produces around 2 million recursion frames and reliably exhausts Go's default 1 GB goroutine stack. The existing allocation budget does not prevent this: each nested collection header costs only a handful of budget units, so the stack is exhausted before the budget is. DAG-JSON has equivalent exposure via `[[[...]]]`-style payloads; it has no budget system and is therefore unprotected against recursion depth as well. Schema-free decoding (using `basicnode.Prototype.Any`) allows arbitrary nesting depth. Schema-bound decoding bounds nesting only when the schema itself is non-recursive and contains no fields typed as `Any`; schemas with recursive type references or any `Any`-typed fields permit unconstrained nesting at those points. The fix adds a configurable `MaxDepth` option to both decoders, defaulting to 1024 nested levels. The decoder returns `ErrDecodeDepthExceeded` when a payload nests beyond the limit. Well-formed IPLD data rarely approaches this depth in practice; the default is generous for legitimate use while preventing stack exhaustion.

Source published

7 May 2026 02:07:21 UTC

Source modified

10 Sep 2026 03:51:07 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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