# CVE-2021-41135: Authz Module Non-Determinism

> Attackers can halt blockchain consensus by exploiting non-deterministic time checks in the authz module, requiring an upgrade to fix.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-2p6r-37p9-89p2

## What is CVE-2021-41135?

CVE-2021-41135 is a medium-severity denial of service vulnerability in cosmos-sdk, published on 20 Oct 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The Cosmos-SDK is a framework for building blockchain applications in Golang. Affected versions of the SDK were vulnerable to a consensus halt due to non-deterministic behaviour in a ValidateBasic method in the x/authz module. The MsgGrant of the x/authz module contains a Grant field which includes a user-defined expiration time for when the authorization grant expires. In Grant.ValidateBasic(), that time is compared to the node’s local clock time. Any chain running an affected version of the SDK with the authz module enabled could be halted by anyone with the ability to send transactions on that chain. Recovery would require applying the patch and rolling back the latest block. Users are advised to update to version 0.44.2.

Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions)

## Which versions are affected by CVE-2021-41135?

2 open source packages ship an affected version, including github.com/cosmos/cosmos-sdk. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/cosmos/cosmos-sdk` | Go | From 0.43.0 | 0.44.2 |
| `github.com/cosmos/cosmos-sdk` | Go | From 0.43.0 | 0.44.2 |

Products: Interchain Cosmos Sdk.

## How do I fix CVE-2021-41135?

Upgrade github.com/cosmos/cosmos-sdk to 0.44.2 or later.

## Is CVE-2021-41135 being exploited?

There is no known exploitation of CVE-2021-41135 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41135 and fix it if it is affected.

What it is: CVE-2021-41135 is a medium-severity denial of service vulnerability in cosmos-sdk, published on 20 Oct 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-41135 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/cosmos/cosmos-sdk (Go): affected from 0.43.0; fixed in 0.44.2
- github.com/cosmos/cosmos-sdk (Go): affected from 0.43.0; fixed in 0.44.2

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/CVE-2021-41135/ (Markdown: https://insights.sbomify.com/CVE-2021-41135/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41135
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41135
- OSV: https://osv.dev/vulnerability/CVE-2021-41135

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41135/
Summaries are generated and may contain mistakes; the official description above is the record.