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

> A null pointer dereference in WebAssembly Binaryen's IRBuilder allows local attackers to cause a denial of service via crafted input.

- **Severity:** Medium 4.8 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Dec 2025
- **Updated:** 24 Feb 2026
- **Also known as:** DEBIAN-CVE-2025-14957, GHSA-3h23-rfwm-gcx3, JLSEC-2026-1093, UBUNTU-CVE-2025-14957

## What is CVE-2025-14957?

CVE-2025-14957 is a medium-severity vulnerability in WebAssembly Binaryen, published on 19 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2025-14957?

It affects 1 product.


Products: Webassembly Binaryen.

## How do I fix CVE-2025-14957?

Apply the vendor's patch.

## Is CVE-2025-14957 being exploited?

There is no known exploitation of CVE-2025-14957 in the wild and no public exploit code.

## Other vulnerabilities in WebAssembly Binaryen

- [CVE-2020-18378](https://insights.sbomify.com/CVE-2020-18378/): Null dereference in n/a (medium 6.5)
- [CVE-2020-18382](https://insights.sbomify.com/CVE-2020-18382/): Memory corruption in n/a (medium 6.5)
- [CVE-2019-15758](https://insights.sbomify.com/CVE-2019-15758/): Denial of service in n/a (medium 6.5)
- [CVE-2019-15759](https://insights.sbomify.com/CVE-2019-15759/): Null dereference in n/a (medium 6.5)
- [CVE-2019-7700](https://insights.sbomify.com/CVE-2019-7700/): Memory corruption in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-14957 and fix it if it is affected.

What it is: CVE-2025-14957 is a medium-severity vulnerability in WebAssembly Binaryen, published on 19 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-14957 in the wild and no public exploit code.

Affected product: WebAssembly Binaryen. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-14957/ (Markdown: https://insights.sbomify.com/CVE-2025-14957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-14957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-14957
- OSV: https://osv.dev/vulnerability/CVE-2025-14957

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-14957/
Summaries are generated and may contain mistakes; the official description above is the record.