StableLib is a stable library of useful TypeScript and JavaScript code. Prior to 2.0.4, the @stablelib/cbor CBOR map decoding path creates ordinary JavaScript objects and assigns attacker-controlled keys with bracket assignment. A map key named __proto__ invokes the inherited prototype setter instead of creating an ordinary own property, allowing the decoded object's prototype to contain attacker-controlled authorization or feature-flag values. Downstream code that trusts normal property lookup or merges the decoded object can therefore make security-sensitive decisions using inherited attacker data. This issue is fixed in version 2.0.4.
History

Fri, 09 Oct 2026 09:15:00 +0000

Type Values Removed Values Added
First Time appeared Stablelib
Stablelib stablelib
Vendors & Products Stablelib
Stablelib stablelib

Wed, 07 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 06 Oct 2026 20:00:00 +0000

Type Values Removed Values Added
Description StableLib is a stable library of useful TypeScript and JavaScript code. Prior to 2.0.4, the @stablelib/cbor CBOR map decoding path creates ordinary JavaScript objects and assigns attacker-controlled keys with bracket assignment. A map key named __proto__ invokes the inherited prototype setter instead of creating an ordinary own property, allowing the decoded object's prototype to contain attacker-controlled authorization or feature-flag values. Downstream code that trusts normal property lookup or merges the decoded object can therefore make security-sensitive decisions using inherited attacker data. This issue is fixed in version 2.0.4.
Title StableLib: Prototype poisoning via `__proto__` map keys in CBOR decoding
Weaknesses CWE-1321
References
Metrics cvssV4_0

{'score': 8.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-06T19:45:02.616Z

Updated: 2026-10-07T17:07:38.703Z

Reserved: 2026-10-06T16:49:40.590Z

Link: CVE-2026-106448

cve-icon Vulnrichment

Updated: 2026-10-07T15:27:17.575Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-06T20:17:26.743

Modified: 2026-10-07T17:16:47.727

Link: CVE-2026-106448

cve-icon Redhat

No data.