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CVE-2026-19481

7.5 · HIGH

@fastify/busboy is a multipart form-data parser.

Published Aug 13, 2026CWE-754EPSS 0.49%

Overview

CVE-2026-19481 is a high-severity vulnerability. It was published on August 13, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

@fastify/busboy is a multipart form-data parser. In versions 1.0.0 through 3.2.0, an attacker who can submit multipart form-data can crash the parser by sending a part header whose name is a prototype-inherited property such as __proto__ or constructor. The internal header parser stores headers in a plain JavaScript object and assumes each value is an array, so an inherited property name resolves to a truthy non-array value and triggers a TypeError. In the common pipe integration the failure surfaces as an error event, but in direct write or end usage the exception is thrown synchronously and can terminate the Node.js process, causing an unauthenticated denial of service. The issue is fixed in @fastify/busboy 3.2.1, which creates the header object with a null prototype. Users should upgrade to 3.2.1.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently asked questions

What is CVE-2026-19481?

CVE-2026-19481 is a high-severity vulnerability. It was published on August 13, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-19481?

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-19481?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-19481?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-19481 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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