CVE-2026-47218

runwasi: Forged Wasmtime precompiled OCI layer bypasses runwasi WASI sandbox

Published Oct 15, 2026 CVSS 4.0 · 9.3 Critical EPSS < 1% KEV · Not listed
Description
runwasi facilitates running Wasm and WASI workloads managed by containerd. Prior to 0.6.1, 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. Downstream shims built with runwasi's containerd-shim-wasm precompile-cache API are also affected if they implement Compiler and trust executable precompiled artifacts from OCI image layers; the 0.6.1 boundary applies specifically to containerd-shim-wasmtime and does not independently certify downstream product releases. The flaw escapes the WASI sandbox to the workload container boundary, but it does not by itself bypass container isolation or provide direct host code execution. This issue is fixed in version 0.6.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
First Time appeared Containerd
Containerd runwasi
Vendors & Products Containerd
Containerd runwasi
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description runwasi facilitates running Wasm and WASI workloads managed by containerd. Prior to 0.6.1, 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. Downstream shims built with runwasi's containerd-shim-wasm precompile-cache API are also affected if they implement Compiler and trust executable precompiled artifacts from OCI image layers; the 0.6.1 boundary applies specifically to containerd-shim-wasmtime and does not independently certify downstream product releases. The flaw escapes the WASI sandbox to the workload container boundary, but it does not by itself bypass container isolation or provide direct host code execution. This issue is fixed in version 0.6.1.
Title runwasi: Forged Wasmtime precompiled OCI layer bypasses runwasi WASI sandbox
Weaknesses CWE-502
References
Metrics cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 15, 2026, 7:55 PM
Reserved
May 18, 2026, 10:25 PM
Status
Awaiting Analysis
Published
Oct 15, 2026, 7:17 PM
Modified
Oct 16, 2026, 4:00 PM