GHSA-x39j-h85h-3f46 is a high-severity (CVSS 7.5) CWE-755 vulnerability in github.com/ipfs/go-merkledag. A fix is available for github.com/ipfs/go-merkledag — see the affected versions and patch details below.
go-merkledag's ProtoNode may be modified such that common method calls may panic
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-x39j-h85h-3f46 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/ipfs/go-merkledagReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
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 and 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.
Additionally, use of the ProtoNode#SetCidBuilder() method to set a non-functioning CidBuilder (such as one that refers to a multihash where an implementation of that hash function is not available) may cause the same methods to panic as a new CID is required but cannot be created.
Patches
Releases involving fixes for this issue are v0.8.0 and v0.8.1. The recommended minimum version is v0.8.1.
- Additional checks are performed on
ProtoNodestate changes to avoid the possibility of creating unencodeable forms, errors are returned where this is the case. - The builder passed in to
SetCidBuilder()is inspected to attempt to determine if it is usable to generate CIDs, otherwise an error is returned. - The panics have been removed and replaced with default values (empty byte slice for
RawData()and a default zero-bytes DAG-PB CID for methods involving CIDs).
Workarounds
These workarounds are available when using impacted versions to avoid panic conditions, and may be generally appropriate in order to provide meaningful feedback to users and avoid generating bad, or unexpected encoded data:
- Sanitise inputs when allowing user-input to set a new
CidBuilderon aProtoNode. - Sanitise
Tsize(Link#Size) values such that they are a reasonable byte-size for sub-DAGs where derived from user-input.
References
- https://github.com/ipfs/kubo/issues/9297
- https://github.com/ipfs/go-merkledag/issues/90
- https://github.com/ipfs/go-merkledag/releases/tag/v0.8.0
- 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://github.com/ipfs/go-merkledag/releases/tag/v0.8.1
Credit
Thanks to @mrd0ll4r for reporting the original error to Kubo!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/ipfs/go-merkledag | ≥ 0.4.0&&< 0.8.1 | 0.8.1go get github.com/ipfs/go-merkledag@v0.8.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/ipfs/go-merkledag, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/ipfs/go-merkledag to 0.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x39j-h85h-3f46 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-x39j-h85h-3f46 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-x39j-h85h-3f46. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-x39j-h85h-3f46 in your dependencies?
O3 Security finds GHSA-x39j-h85h-3f46 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.