---
id: CVE-2026-106448
title: StableLib is a stable library of useful TypeScript and JavaScript code
summary: >-
  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 ke…
severity: high
cvss: 8.9
cvssVector: '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'
cwe:
  - CWE-1321
vendor: StableLib
product: stablelib
affected:
  - stablelib < 2.0.4
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T20:17:26.743'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-106448'
references:
  - url: >-
      https://github.com/StableLib/stablelib/commit/0f153a63b7552a0e8721f640984113e419015026
    label: security-advisories@github.com
  - url: 'https://github.com/StableLib/stablelib/releases/tag/@stablelib/cbor@2.0.4'
    label: security-advisories@github.com
  - url: >-
      https://github.com/StableLib/stablelib/security/advisories/GHSA-w48f-fwg7-ww6p
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
cvssSource: cna
ingestedAt: '2026-10-06T20:16:42.481Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.