Browserslist: Uncaught crash / prototype write via untrusted browserslist-stats.json custom stats (normalizeStats)

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-73088
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-11 17:19:16 UTC
Updated2026-08-11 17:19:16 UTC
DescriptionBrowserslist 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-248 | CWE-1321 | CWE-1321 CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') | CWE-248 CWE-248: Uncaught Exception

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Browserslist Browserslist affected < 4.28.7 Not specified

References

ReferenceSourceLinkTags
github.com/browserslist/browserslist/releases/tag/4.28.7 [email protected] github.com
github.com/browserslist/browserslist/commit/f9914ad9effc865ccc27d8162556... [email protected] github.com
github.com/browserslist/browserslist/security/advisories/GHSA-73wf-gq98-... [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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