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CVE-2026-106448

StableLib: Prototype poisoning via `__proto__` map keys in CBOR decoding PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
StableLib / stablelibaffected < 2.0.4

CWE

CWE-1321

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.