CVE-2026-119140 bytecodealliance CVE debrief

Who should care

Defenders responsible for Wasmtime deployments should assess exposure and prioritize patching or updating to fixed versions. They should verify Wasmtime versions and configurations to ensure security and monitor for potential host panics. Defenders should also review compensating controls for exposed systems and track exceptions and retest remediated assets. The vulnerability affects operators, platforms, and security teams that use Wasmtime, and they must

Why it matters

The vulnerability in Wasmtime can lead to host panics, requiring defenders to assess exposure, prioritize patching, and verify configurations to ensure security.

• Potential host panics require verification and mitigation
• Exposure assessment and patching are necessary to prevent potential issues
• Defenders should verify Wasmtime versions and configurations to ensure security

Technical summary

The vulnerability occurs when yielding in a component start function in Wasmtime, leading to a host panic. The affected versions are between 46.0.0 and 48.0.6 and 49.0.0 and 49.0.3. Patches are available in versions 48.0.6 and 49.0.3. Defenders should prioritize verifying the versions of Wasmtime in use and assessing exposure, as the vulnerability can cause a host panic. The vulnerability can be mitigated by updating to fixed versions or applying patches. The fix involves updating the Wasmtime configuration to prevent yielding in component start functions.

Defensive priority

Defenders should prioritize verifying the versions of Wasmtime in use and assessing exposure, as the vulnerability can cause a host panic.

Recommended defensive actions

• Verify Wasmtime versions in use and assess exposure
• Review and apply patches or updates for Wasmtime
• Monitor for potential host panics and adjust configurations as needed
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability is described in the RustSec database and the Wasmtime security advisory on GitHub. The advisory provides details on the affected versions and the fix. The RustSec database entry provides additional context on the vulnerability and its impact. Defenders should verify Wasmtime versions and configurations to ensure security.

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.