---
id: CVE-2026-54914
title: >-
  WebAssembly Micro Runtime: Heap Buffer Overflow in WAMR WASI poll_oneoff
  Output Buffer
summary: >-
  WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly
  (Wasm) runtime. Prior to 2.4.5, wasi_poll_oneoff in
  core/iwasm/libraries/libc-wasi/libc_wasi_wrapper.c validates the output
  pointer for only one wasi_event_t, while…
severity: high
cvss: 8.3
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-122
vendor: bytecodealliance
product: wasm-micro-runtime
affected:
  - wasm-micro-runtime < 2.4.5
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T17:27:16.493Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-54914'
references:
  - url: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-wj3p-xhqm-pffc
    label: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-wj3p-xhqm-pffc
  - url: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/1f98fb01d09b2ef5e49dc0be2e6006f962fd87f1
    label: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/1f98fb01d09b2ef5e49dc0be2e6006f962fd87f1
  - url: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b49d10eac4176817305d60ea59d24bc69a53eb7b
    label: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b49d10eac4176817305d60ea59d24bc69a53eb7b
  - url: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5
    label: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5
tags:
  - cve.org
ingestedAt: '2026-11-05T22:38:31.438Z'
---

## Overview

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, wasi_poll_oneoff in core/iwasm/libraries/libc-wasi/libc_wasi_wrapper.c validates the output pointer for only one wasi_event_t, while wasmtime_ssp_poll_oneoff in core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/posix.c can write as many events as the guest-controlled nsubscriptions value. A crafted guest module can provide multiple subscriptions that produce events while positioning an output region large enough for only one event, causing a later out[nevents] write to cross the validated Wasm linear-memory boundary into adjacent host heap memory. The overwrite contains partly attacker-controlled event data and can reliably crash the host process, with further confidentiality or integrity consequences depending on heap layout. This issue is fixed in version 2.4.5.

## Affected

- `wasm-micro-runtime < 2.4.5`

## Remediation

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