MEDIUM

GHSA-mx2j-7cmv-353c

wasmvm: Malicious smart contract can slow down block production

Quick fix

GHSA-mx2j-7cmv-353c — github.com/CosmWasm/wasmvm: upgrade to the fixed version with the command below.

go get github.com/CosmWasm/wasmvm@v1.5.8

Details

# CWA-2025-002

**Severity**

Medium (Moderate + Likely)[^1]

**Affected versions:**

- wasmvm >= 2.2.0, < 2.2.2 - wasmvm >= 2.1.0, < 2.1.5 - wasmvm >= 2.0.0, < 2.0.6 - wasmvm < 1.5.8

**Patched versions:**

- wasmvm 1.5.8, 2.0.6, 2.1.5, 2.2.2

## Description of the bug

The vulnerability can be used to slow down block production. The attack requires a malicious contract, so permissioned chains are unlikely to be affected.

(We'll add more detail once chains had a chance to upgrade.)

## Patch

- 1.5: https://github.com/CosmWasm/cosmwasm/commit/2b7f2faa57a1efc8207455c37f87f1eee6035a27 - 2.0: https://github.com/CosmWasm/cosmwasm/commit/d6143b0aff16a39bbea4be37597d8e9d9b213d3b - 2.1: https://github.com/CosmWasm/cosmwasm/commit/f0c04c03cbe2557634c1bbcdc2ce203fe7caca58 - 2.2: https://github.com/CosmWasm/cosmwasm/commit/a5d62f65b5eb947ebe40e2085b1c48a9d0a244d0

## Applying the patch

The patch will be shipped in releases of wasmvm. You can update more or less as follows:

1. Check the current wasmvm version: `go list -m github.com/CosmWasm/wasmvm` 2. Bump the `github.com/CosmWasm/wasmvm` dependency in your go.mod to one of the patched version depending on which minor version you are on; `go mod tidy`; commit. 3. If you use the static libraries `libwasmvm_muslc.aarch64.a`/`libwasmvm_muslc.x86_64.a`, update them accordingly. 4. Check the updated wasmvm version: `go list -m github.com/CosmWasm/wasmvm` and ensure you see 1.5.8, 2.0.6, 2.1.5 or 2.2.2. 5. Follow your regular practices to deploy chain upgrades.

The patch is consensus breaking and requires a coordinated upgrade.

## Acknowledgement

This issue was found by meadow101 who reported it to the Cosmos Bug Bounty Program on HackerOne.

If you believe you have found a bug in the Interchain Stack or would like to contribute to the program by reporting a bug, please see <https://hackerone.com/cosmos>.

## Timeline

- 2024-11-24: Confio receives a report through the Cosmos bug bounty program maintained by Amulet. - 2024-12-20: Confio security contributors confirm the report. - 2024-01-27: Confio developed the patch internally. - 2025-02-04: Patch gets released.

[^1]: following Amulet's Severity Classification Framework ACMv1.2: https://github.com/interchainio/security/blob/0295254e8645301ccb606d46108a45cede0a73e0/resources/CLASSIFICATION_MATRIX.md