CVE-2026-47218 containerd CVE debrief

Who should care

Containerd users who have runwasi installed should be aware of this critical vulnerability and take immediate action to upgrade to version 0.6.1 or later to prevent exploitation. This vulnerability can allow an attacker to bypass the WASI sandbox and execute native code in the shim zygote process, potentially gaining access to sensitive data and disrupting system operations. Affected operators, platforms, vulnerability-management teams, and security teams,

Why it matters

CVE-2026-47218 is a critical vulnerability in runwasi that allows an attacker to bypass the WASI sandbox and execute native code in the shim zygote process. This issue requires immediate attention from containerd users who have runwasi installed.

• Execution of native code in the shim zygote process
• Bypassing of WebAssembly validation
• Access to filesystem, environment, credentials, networking, and Linux syscall

Technical summary

The vulnerability exists in runwasi prior to version 0.6.1, where containerd-shim-wasmtime-v1 can treat Wasmtime precompiled bytes supplied directly in an OCI image layer as a trusted artifact from the precompile-cache path and deserialize them as native code. An attacker who causes a victim to run a crafted image can bypass WebAssembly validation and execute native code in the shim zygote process, gaining the filesystem, environment, credentials, networking, and Linux syscall access available to the workload container.

Defensive priority

High

Recommended defensive actions

• Upgrade runwasi to version 0.6.1 or later
• Restrict access to containerd-shim-wasmtime-v1
• Monitor for suspicious activity in containerd-shim-wasmtime-v1 logs
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability exists in runwasi prior to version 0.6.1. An attacker can exploit this issue by causing a victim to run a crafted image, allowing them to bypass WebAssembly validation and execute native code in the shim zygote process.

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.