---
id: CVE-2026-54912
title: >-
  WAMR fast interpreter loader heap buffer overflow via constant deduplication
  mismatch
summary: >-
  WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly
  (Wasm) runtime. Prior to 2.4.5, the two-pass fast interpreter loader in
  core/iwasm/interpreter/wasm_loader.c can make inconsistent constant-table
  decisions between …
severity: high
cvss: 8.8
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-787
vendor: bytecodealliance
product: wasm-micro-runtime
affected:
  - wasm-micro-runtime < 2.4.5
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-11-05T18:42:22.842506Z'
exploitAvailable: true
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T18:44:51.857Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-54912'
references:
  - url: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-jjv3-x3jf-cg49
    label: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-jjv3-x3jf-cg49
  - url: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b1353b5e8983047ff68829c99abf1355d5f389cf
    label: >-
      https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b1353b5e8983047ff68829c99abf1355d5f389cf
  - url: 'https://gist.github.com/shumbo/b710c35b005ed871447fce385d1ab760'
    label: 'https://gist.github.com/shumbo/b710c35b005ed871447fce385d1ab760'
  - 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
  - exploit-available
ingestedAt: '2026-11-05T22:38:31.476Z'
---

## Overview

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, the two-pass fast interpreter loader in core/iwasm/interpreter/wasm_loader.c can make inconsistent constant-table decisions between the sizing pass and the emitting pass. After duplicate constants inflate the first pass beyond the constant-slot limit, wasm_loader_get_const_offset emits later constants inline, but the between-pass sort and deduplication reduces the table so the second pass can choose table references and cause reserve_block_ret to emit additional copy operands that were not included in code_compiled_peak_size. A crafted module can therefore make the second pass write partially attacker-controlled compiled-code data beyond the heap buffer allocated from the first pass's size calculation during wasm_runtime_load, before guest code executes. This can corrupt host heap metadata and deterministically crash the process, causing denial of service; further consequences depend on the host application's heap layout. Builds using WAMR_BUILD_FAST_INTERP=1 are affected; disabling the fast interpreter avoids the vulnerable loader. 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.