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

> A heap-based buffer overflow in WebAssembly Binaryen allows local attackers to execute arbitrary code or cause denial of service via crafted binaries.

- **Severity:** Medium 4.8 (`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`)
- **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-2025-14956, GHSA-vjgx-vcpf-hm6w, JLSEC-2026-1092, UBUNTU-CVE-2025-14956

## What is CVE-2025-14956?

CVE-2025-14956 is a medium-severity memory corruption 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 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.

Weakness: CWE-125 (Out-of-bounds Read), CWE-122 (Heap-based Buffer Overflow), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2025-14956?

It affects 1 product.


Products: Webassembly Binaryen.

## How do I fix CVE-2025-14956?

Apply the vendor's patch.

## Is CVE-2025-14956 being exploited?

There is no known exploitation of CVE-2025-14956 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-2025-14956 and fix it if it is affected.

What it is: CVE-2025-14956 is a medium-severity memory corruption 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-2025-14956 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-2025-14956/ (Markdown: https://insights.sbomify.com/CVE-2025-14956/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-14956
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-14956
- OSV: https://osv.dev/vulnerability/CVE-2025-14956

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-14956/
Summaries are generated and may contain mistakes; the official description above is the record.