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.
Published: 2026-10-06
Score: 8.9 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

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'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

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

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

Link: CVE-2026-106448

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-106448

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-1321

    Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')