CVE-2026-115892 bytecodealliance CVE debrief

Who should care

Defenders responsible for Wasmtime deployments, particularly those using embedders that create and pass streams or futures between host and guest code, should assess exposure and verify versions.

Why it matters

Defenders should care about this vulnerability as it can lead to potential denials of service, data corruption, or unexpected behavior in Wasmtime deployments. The vulnerability requires verification and updating of Wasmtime versions, particularly for embedders that handle streams or futures between host and guest code.

• Potential denial of service due to panics
• Need for verification and updating of Wasmtime versions
• Possible data corruption or unexpected behavior due to type mismatches

Technical summary

The vulnerability occurs when a host-created component model stream or future is lowered into a guest with a different payload type. This can happen when an embedder creates a stream or future, passes it through a guest, receives it back under a type-erased type, and then passes it to a guest function with a different payload type. The vulnerability requires verification and updating of Wasmtime versions, particularly for embedders that handle streams or futures between host and guest code. Defenders should prioritize verifying and updating Wasmtime versions to prevent potential panics.

Defensive priority

Defenders should prioritize verifying and updating Wasmtime versions to prevent potential panics.

Recommended defensive actions

• Verify and update Wasmtime versions to ensure they are not vulnerable
• Review and update embedder code to handle type mismatches correctly
• Monitor for potential panics and implement error handling
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The source corpus provides details on the vulnerability, including the conditions under which a panic may occur and the affected versions of Wasmtime. Defenders should verify and update Wasmtime versions to ensure they are not vulnerable. The vulnerability can lead to potential denials of service, data corruption, or unexpected behavior in Wasmtime deployments.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.