CVE-2026-73088: Browserslist

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

Browserslist is a configuration tool for sharing target browsers and Node.js versions between front-end tools. Prior to 4.28.7, normalizeStats() in node.js, reached unconditionally through getStat() and loadStat() on every browserslist() call, processes untrusted browserslist-stats.json, opts.stats, and CLI --stats data with an unguarded for...in loop and plain-object bracket access and assignment, allowing inherited Object.prototype keys including __proto__, toString, valueOf, constructor, hasOwnProperty, and isPrototypeOf to cause an uncaught TypeError or modify the prototype of the returned normalized object. This issue is fixed in version 4.28.7.

Affected products

• Browserslist Browserslist: before 4.28.7 (fixed in 4.28.7)

Published 2026-08-11. Last modified 2026-09-09.