---
id: CVE-2026-115383
title: >-
  Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 GC Heap Corruption via
  Tag Imports
summary: >-
  Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains an improper
  validation vulnerability that accepts components whose core modules import
  WebAssembly tags with a subtype of the original type. Malicious guests can
  mis-type ex…
severity: medium
cvss: 4.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-1287
vendor: bytecodealliance
product: wasmtime
affected:
  - wasmtime >= 47.0.0 < 48.0.4
  - wasmtime >= 49.0.0 < 49.0.2
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T19:13:50.687Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115383'
references:
  - url: >-
      https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-cfhf-m2cr-62wj
    label: GitHub Security Advisory (GHSA-cfhf-m2cr-62wj)
  - url: >-
      https://www.vulncheck.com/advisories/wasmtime-47.0.0-before-48.0.4-and-49.0.0-before-49.0.2-gc-heap-corruption-via-tag-imports
    label: >-
      VulnCheck Advisory: Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2
      GC Heap Corruption via Tag Imports
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.403Z'
---

## Overview

Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains an improper validation vulnerability that accepts components whose core modules import WebAssembly tags with a subtype of the original type. Malicious guests can mis-type exception object payloads to corrupt the GC heap, causing Wasmtime to panic when the exceptions proposal is enabled.

## Affected

- `wasmtime >= 47.0.0 < 48.0.4`
- `wasmtime >= 49.0.0 < 49.0.2`

## Remediation

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