wasmvm: Malicious smart contract can crash the chain

Summary

# CWA-2025-001

**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 crash the chain. The underlying bug that causes this is present on both permissioned and premissionless chains, but it can only be triggered _reliably_ with a malicious contract, so permissioned chains are much less likely to be affected.

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

## Patch

- 1.5: https://github.com/CosmWasm/wasmvm/commit/1151bc6df7d02d1889b8da37cf8510eaf4198eea - 2.0: https://github.com/CosmWasm/wasmvm/commit/d4ff2adee44e6b9f7415a5dfbb3de745ab9b7678 - 2.1: https://github.com/CosmWasm/wasmvm/commit/8d44a286fabc793a2fba93752e58cd0fd5b88a2d - 2.2: https://github.com/CosmWasm/wasmvm/commit/0aefa4c378457aeb3c07e7975b875be38872c56d

## 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.

While the fix for this issue is not consensus breaking, the patch contains another consensus breaking fix 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

- 2024-11-25: Confio receives a report through the Cosmos bug bounty program maintained by Amulet. - 2024-11-28: Confio security contributors confirm the report. - 2024-11-28: 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