---
id: CVE-2026-115389
title: >-
  Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Denial
  of Service via Val API
summary: >-
  Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does
  not adequately account for host allocations when lifting guest values through
  the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious
  WebA…
severity: low
cvss: 2.3
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-770
vendor: bytecodealliance
product: wasmtime
affected:
  - wasmtime < 36.0.16
  - wasmtime >= 37.0.0 < 48.0.3
  - wasmtime >= 49.0.0 < 49.0.1
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T19:13:55.163Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115389'
references:
  - url: >-
      https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jqpg-j7w6-42pr
    label: GitHub Security Advisory (GHSA-jqpg-j7w6-42pr)
  - url: >-
      https://www.vulncheck.com/advisories/wasmtime-before-36.0.16-37.0.0-before-48.0.3-and-49.0.0-before-49.0.1-denial-of-service-via-val-api
    label: >-
      VulnCheck Advisory: Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and
      49.0.0 before 49.0.1 Denial of Service via Val API
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.405Z'
---

## Overview

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing denial of service.

## Affected

- `wasmtime < 36.0.16`
- `wasmtime >= 37.0.0 < 48.0.3`
- `wasmtime >= 49.0.0 < 49.0.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.