---
id: CVE-2026-115381
title: >-
  Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2
  Unbounded Host Memory Allocation via SinkOutputStream write-zeroes
summary: >-
  Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2
  contains an unbounded memory allocation in the wasmtime-wasi WASIp2
  write-zeroes method of SinkOutputStream, the default stream used when
  stdout/stderr are not confi…
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-770
vendor: bytecodealliance
product: wasmtime
affected:
  - wasmtime < 36.0.17
  - wasmtime >= 37.0.0 < 48.0.4
  - wasmtime >= 49.0.0 < 49.0.2
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T19:13:49.244Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115381'
references:
  - url: >-
      https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-gqmc-89g8-p25r
    label: GitHub Security Advisory (GHSA-gqmc-89g8-p25r)
  - url: >-
      https://www.vulncheck.com/advisories/wasmtime-before-36.0.17-37.0.0-before-48.0.4-and-49.0.0-before-49.0.2-unbounded-host-memory-allocation-via-sinkoutputstream-write-zeroes
    label: >-
      VulnCheck Advisory: Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and
      49.0.0 before 49.0.2 Unbounded Host Memory Allocation via SinkOutputStream
      write-zeroes
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.403Z'
---

## Overview

Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an unbounded memory allocation in the wasmtime-wasi WASIp2 write-zeroes method of SinkOutputStream, the default stream used when stdout/stderr are not configured. A malicious WebAssembly guest can request huge zero-filled writes, exhausting host memory and causing denial of service.

## Affected

- `wasmtime < 36.0.17`
- `wasmtime >= 37.0.0 < 48.0.4`
- `wasmtime >= 49.0.0 < 49.0.2`

## Remediation

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