MrSwitch hello.js vulnerable to prototype pollution

CRITICAL 9.8CVE-2021-26505 · GHSA-g3vf-47fv-8f3c · Published 11/08/2023 · updated 17/06/2026

In short

CVE-2021-26505 is a CRITICAL (CVSS 9.8) vulnerability affecting hello.js (hello.js project), hellojs.
Chance of exploitation in the next 30 days (EPSS): 1.1%, higher than 66.9% of all vulnerabilities.
Fix: update to 1.18.8 or later.

Package	Affected versions	Patched versions
hello.js hello.js_project	`= 1.18.6`	No fix yet
hellojs npm	`< 1.18.8`	`1.18.8`

Description

A prototype pollution vulnerability in MrSwitch hello.js prior to version 1.18.8 allows remote attackers to execute arbitrary code via hello.utils.extend function.

NVD description

Prototype pollution vulnerability in MrSwitch hello.js version 1.18.6, allows remote attackers to execute arbitrary code via hello.utils.extend function.

References

nvd.nist.gov/vuln/detail/CVE-2021-26505 · ADVISORY
MrSwitch/hello.js · WEB
MrSwitch/hello.js commit 7ab50ae · WEB
MrSwitch/hello.js · PACKAGE

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