# CVE-2026-89418: Uncontrolled Recursion leading to Denial of Service in protobuf-javascript (google-protobuf)

> An attacker can crash Node.js services using google-protobuf by sending crafted deeply nested group fields, causing uncontrolled recursion and process termination.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** AZL-103491, ROOT-APP-NPM-CVE-2026-89418

## What is CVE-2026-89418?

CVE-2026-89418 is a high-severity denial of service vulnerability in protobuf-javascript (aka google-protobuf npm package), published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

google-protobuf contains an unbounded recursion when parsing unknown protobuf group fields. An attacker can send a small crafted payload of deeply nested START_GROUP wire bytes to any Node.js service that calls the generated deserializeBinary() API, causing a RangeError: Maximum call stack size exceeded and crashing the process. No authentication or prior knowledge of the schema is required.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-89418?


## How do I fix CVE-2026-89418?

Upgrade to a fixed version.

## Is CVE-2026-89418 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89418 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89418 and fix it if it is affected.

What it is: CVE-2026-89418 is a high-severity denial of service vulnerability in protobuf-javascript (aka google-protobuf npm package), published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89418 exists.

Affected product: protobuf-javascript (aka google-protobuf npm package). 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-2026-89418/ (Markdown: https://insights.sbomify.com/CVE-2026-89418/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89418
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89418
- OSV: https://osv.dev/vulnerability/CVE-2026-89418

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-89418/
Summaries are generated and may contain mistakes; the official description above is the record.