CVE-2026-106448

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.

CVSS 4.0

8.9CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 34% of CVEs (scores of 2026-10-25)

CWE

CWE-1321

Published

2026-10-06

Modified

2026-10-07

Record from

the NVD, synced 2026-10-19

Packages (OSV)

References

• https://github.com/StableLib/stablelib/commit/0f153a63b7552a0e8721f640984113e419015026
• https://github.com/StableLib/stablelib/releases/tag/@stablelib/cbor@2.0.4
• https://github.com/StableLib/stablelib/security/advisories/GHSA-w48f-fwg7-ww6p

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