9.3

CVE-2026-47218: runwasi: Forged Wasmtime precompiled OCI layer bypasses runwasi WASI sandbox

Awaiting analysis
Published 15-10-2026Last modified 15-10-2026

Vulnerability summary

CVE-2026-47218 is a critical (CVSS 9.3) Deserialization of Untrusted Data vulnerability in containerd runwasi. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 33.6% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.3 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.3/10
010
Critical · v4.0 (CVE.org)
EPSS score
0.39%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 15-10-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.39%

Chance of exploitation in the next 30 days

Percentile

34%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

16-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Containerd1 product

1 vendor · 1 product

References

3 links