CVE-2020-8136Public exploitNetwork attack vector

Remote server crash via prototype-poisoning field name

Published Mar 20, 2020 · Updated Aug 4, 2024

Prototype pollution in Fastify @fastify/multipart before 1.0.5 allows remote attackers to crash servers via crafted multipart requests. With addToBody enabled, the parser assigns a part named proto into the request-body object, changing its prototype before application code uses that body. An unauthenticated request to an endpoint parsing multipart form data with this option can terminate the Node.js process, with no reported confidentiality or integrity impact.

CVSS severity7.5
High
EPSS probability1.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in Fastify @fastify/multipart before 1.0.5 allows remote attackers to crash servers via crafted multipart requests. With addToBody enabled, the parser assigns a part named proto into the request-body object, changing its prototype before application code uses that body. An unauthenticated request to an endpoint parsing multipart form data with this option can terminate the Node.js process, with no reported confidentiality or integrity impact.

The record

CVE
CVE-2020-8136
Published
Mar 20, 2020
Updated
Aug 4, 2024
Vendor
Fastify
Product
@fastify/multipart
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 20, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Fixed version: 1.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fastify · @fastify/multipartversion=Fixed version: 1.0.5

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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