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find-my-way: DDoS with HTTP2

High severity GitHub Reviewed Published Jul 22, 2026 in delvedor/find-my-way

Package

npm find-my-way (npm)

Affected versions

<= 9.6.0

Patched versions

9.7.0

Description

Impact

Remotely triggerable DoS in find-my-way when it is used with Node's HTTP/2 server.

The short version is that lookup() passes req.method into find(), and find() indexes this.trees[method]. Since this.trees is a normal object, HTTP/2 method values like constructor, toString, or __proto__ can resolve inherited object properties instead of returning undefined. The code then treats that value like a router node and crashes when it reaches currentNode.prefix.length.

Patches

Upgrade to v9.7.0.

Workarounds

Do not use find-my-way with HTTP/2 servers, or validate that the http method is valid beforehand.

References

@delvedor delvedor published to delvedor/find-my-way Jul 22, 2026
Published to the GitHub Advisory Database Jul 23, 2026
Reviewed Jul 23, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(38th percentile)

Weaknesses

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. Learn more on MITRE.

CVE ID

CVE-2026-47219

GHSA ID

GHSA-c96f-x56v-gq3h

Source code

Credits

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