---
id: CVE-2026-115391
aliases:
  - RUSTSEC-2026-0268
  - GHSA-x84v-gj2h-g759
title: Guest controlled-size host heap allocation through WASIp3 streams
summary: Guest controlled-size host heap allocation through WASIp3 streams
severity: medium
cvss: 5.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H'
vendor: wasmtime
product: wasmtime
ecosystem: rust
affected:
  - 'wasmtime >= 47.0.0, < 47.0.4'
patched:
  - wasmtime 47.0.4
published: '2026-08-20'
updated: '2026-10-24'
sourceUpdated: '2026-10-24T06:25:41Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/RUSTSEC-2026-0268'
references:
  - url: 'https://crates.io/crates/wasmtime'
  - url: 'https://rustsec.org/advisories/RUSTSEC-2026-0268.html'
  - url: 'https://github.com/bytecodealliance/wasmtime/pull/14181'
  - url: >-
      https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-x84v-gj2h-g759
    label: GitHub Security Advisory (GHSA-x84v-gj2h-g759)
  - url: >-
      https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-46.0.3-and-47.0.0-before-47.0.4-unbounded-heap-allocation-via-wasip3-streams
    label: >-
      VulnCheck Advisory: Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4
      Unbounded Heap Allocation via WASIp3 Streams
tags:
  - osv
  - rust
  - cve.org
epss: 0.00172
epssPercentile: 0.06548
cvssSource: cna
cwe:
  - CWE-770
ingestedAt: '2026-10-22T22:00:50.406Z'
---

## Overview

This is an entry in the RustSec database for the Wasmtime security advisory
located at
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-x84v-gj2h-g759
For more information see the GitHub-hosted security advisory.

## Affected packages

- `wasmtime >= 47.0.0, < 47.0.4`

## Remediation

Upgrade to a patched release:

- `wasmtime 47.0.4`