GHSA-mx2j-7cmv-353c: wasmvm: Malicious smart contract can slow down block production

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.