CVE-2022-23495

CVE-2022-23495 is a high-severity security vulnerability in github.com/ipfs/go-merkledag (go), affecting versions >= 0.4.0, < 0.8.1. It is fixed in 0.8.1.

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Summary

go-merkledag's ProtoNode may be modified such that common method calls may panic

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 CidBuilder on a ProtoNode.
  • Sanitise Tsize (Link#Size) values such that they are a reasonable byte-size for sub-DAGs where derived from user-input.

References

Credit

Thanks to @mrd0ll4r for reporting the original error to Kubo!

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.

CVE-2022-23495 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.8.1); upgrading removes the vulnerable code path.

Affected versions

github.com/ipfs/go-merkledag (>= 0.4.0, < 0.8.1)

Security releases

github.com/ipfs/go-merkledag → 0.8.1 (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

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 ProtoNode state 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).

Frequently Asked Questions

  1. What is CVE-2022-23495? CVE-2022-23495 is a high-severity security vulnerability in github.com/ipfs/go-merkledag (go), affecting versions >= 0.4.0, < 0.8.1. It is fixed in 0.8.1.
  2. How severe is CVE-2022-23495? CVE-2022-23495 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which versions of github.com/ipfs/go-merkledag are affected by CVE-2022-23495? github.com/ipfs/go-merkledag (go) versions >= 0.4.0, < 0.8.1 is affected.
  4. Is there a fix for CVE-2022-23495? Yes. CVE-2022-23495 is fixed in 0.8.1. Upgrade to this version or later.
  5. Is CVE-2022-23495 exploitable, and should I be worried? Whether CVE-2022-23495 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2022-23495 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2022-23495? Upgrade github.com/ipfs/go-merkledag to 0.8.1 or later.

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