# GHSA-r9rv-9mh8-pxf4: Nervos CKB BlockTimeTooNew should not be considered as invalid block

> An attacker can split the network by mining blocks slightly ahead of time, causing nodes to ban legitimate peers and disrupt connectivity.

- **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:** 2 Feb 2024

## What is GHSA-r9rv-9mh8-pxf4?

GHSA-r9rv-9mh8-pxf4 is a denial of service vulnerability in ckb, published on 2 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

### Impact

Currently, when a node receives a block in future according to its local wall clock, it will mark the block as invalid and ban the peer. 

If the header's timestamp is more than 15 seconds ahead of our current time. In that case, the header may become valid in the future, and we don't want to disconnect a peer merely for serving us one too-far-ahead block header, to prevent an attacker from splitting the network by mining a block right at the  15 seconds boundary.

### Patches

Upgrade to v0.33.1 or above.

### Workarounds
Don't ban peer serving too-far-ahead block header.

## Which versions are affected by GHSA-r9rv-9mh8-pxf4?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ckb` | crates.io | All versions | 0.33.1 |
| `ckb` | crates.io | All versions | 0.33.1 |

## How do I fix GHSA-r9rv-9mh8-pxf4?

Upgrade ckb to 0.33.1 or later.

## Is GHSA-r9rv-9mh8-pxf4 being exploited?

There is no known exploitation of GHSA-r9rv-9mh8-pxf4 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-r9rv-9mh8-pxf4 and fix it if it is affected.

What it is: GHSA-r9rv-9mh8-pxf4 is a denial of service vulnerability in ckb, published on 2 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-r9rv-9mh8-pxf4 in the wild and no public exploit code.

Affected packages and fixed versions:
- ckb (crates.io): affected all versions; fixed in 0.33.1
- ckb (crates.io): affected all versions; fixed in 0.33.1

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-r9rv-9mh8-pxf4/ (Markdown: https://insights.sbomify.com/GHSA-r9rv-9mh8-pxf4/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-r9rv-9mh8-pxf4

---
From sbomify Insights: https://insights.sbomify.com/GHSA-r9rv-9mh8-pxf4/
Summaries are generated and may contain mistakes; the official description above is the record.