---
id: CVE-2026-42328
aliases:
  - GHSA-w239-58x2-q8p5
  - GO-2026-5684
title: go-ipld-prime's DAG-CBOR and DAG-JSON decoders have unbounded recursion depth
summary: go-ipld-prime's DAG-CBOR and DAG-JSON decoders have unbounded recursion depth
severity: medium
cvss: 6.2
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: ipld
product: github.com/ipld/go-ipld-prime
ecosystem: go
affected:
  - github.com/ipld/go-ipld-prime < 0.23.0
patched:
  - github.com/ipld/go-ipld-prime 0.23.0
published: '2026-05-07'
updated: '2026-07-24'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-w239-58x2-q8p5'
references:
  - url: >-
      https://github.com/ipld/go-ipld-prime/security/advisories/GHSA-w239-58x2-q8p5
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42328'
  - url: 'https://github.com/ipld/go-ipld-prime'
tags:
  - osv
  - go
epss: 0.0012
epssPercentile: 0.02094
ingestedAt: '2026-07-25T19:08:12.029Z'
---

## Overview

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.

## Affected packages

- `github.com/ipld/go-ipld-prime < 0.23.0`

## Remediation

Upgrade to a patched release:

- `github.com/ipld/go-ipld-prime 0.23.0`