CVE-2026-106448

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 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.

Affected Software

VendorProductVersion RangeStatus
StableLibstablelib< 2.0.4affected

Weaknesses

  • CWE-1321: CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

References