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.
History

Mon, 17 Aug 2026 11:45:00 +0000

Type Values Removed Values Added
First Time appeared Browserslist Project
Browserslist Project browserslist
Vendors & Products Browserslist Project
Browserslist Project browserslist

Thu, 13 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 13 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-915
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

threat_severity

Important


Tue, 11 Aug 2026 17:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Browserslist: Uncaught crash / prototype write via untrusted browserslist-stats.json custom stats (normalizeStats)
Weaknesses CWE-1321
CWE-248
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-08-11T17:00:05.869Z

Updated: 2026-08-13T14:50:43.387Z

Reserved: 2026-08-10T19:37:41.445Z

Link: CVE-2026-73088

cve-icon Vulnrichment

Updated: 2026-08-13T14:50:19.893Z

cve-icon NVD

Status : Received

Published: 2026-08-11T17:19:16.977

Modified: 2026-08-13T15:20:06.333

Link: CVE-2026-73088

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-11T17:00:05Z

Links: CVE-2026-73088 - Bugzilla