# GHSA-3gjh-29fv-8hr6: Nervos CKB Snappy decompress length can be very large and causes out of memory error

> An attacker can cause a denial of service by sending compressed messages that expand to consume excessive memory, crashing the Nervos CKB node.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Feb 2024

## What is GHSA-3gjh-29fv-8hr6?

GHSA-3gjh-29fv-8hr6 is a denial of service vulnerability in ckb, published on 3 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

### Impact

Adversary can create message which compressed size is less than the package limit but the decompressed length is very large such as 1G. It will cost the node many memories to process the network messages, and on the system with less than 1G memory, the process is killed directly because of out of memory error.

### Patches

The node must check the decompress length before allocating the memory for the message.

### References

* https://github.com/nervosnetwork/ckb/blob/687d797f1888dd05d1f38ce6d1bef3e5b9b6e38b/network/src/compress.rs#L68
* https://github.com/BurntSushi/rust-snappy/blob/master/src/decompress.rs#L106
* https://github.com/BurntSushi/rust-snappy/blob/6cfb836463b9b3ac48ca7cd15d0a50d030e95769/src/decompress.rs#L30

## Which versions are affected by GHSA-3gjh-29fv-8hr6?

2 open source packages ship an affected version, including ckb.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ckb` | crates.io | All versions | 0.34.2 |
| `ckb` | crates.io | All versions | 0.34.2 |

## How do I fix GHSA-3gjh-29fv-8hr6?

Upgrade ckb to 0.34.2 or later.

## Is GHSA-3gjh-29fv-8hr6 being exploited?

There is no known exploitation of GHSA-3gjh-29fv-8hr6 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-3gjh-29fv-8hr6 and fix it if it is affected.

What it is: GHSA-3gjh-29fv-8hr6 is a denial of service vulnerability in ckb, published on 3 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-3gjh-29fv-8hr6 in the wild and no public exploit code.

Affected packages and fixed versions:
- ckb (crates.io): affected all versions; fixed in 0.34.2
- ckb (crates.io): affected all versions; fixed in 0.34.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-3gjh-29fv-8hr6/ (Markdown: https://insights.sbomify.com/GHSA-3gjh-29fv-8hr6/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-3gjh-29fv-8hr6

---
From sbomify Insights: https://insights.sbomify.com/GHSA-3gjh-29fv-8hr6/
Summaries are generated and may contain mistakes; the official description above is the record.