CVE-2026-29063
CRITICAL severity · CVSS 9.8 · Prototype pollution
9.8CVSS CRITICAL
Summary
Immutable.js provides many Persistent Immutable data structures. Prior to versions 3.8.3, 4.3.7, and 5.1.5, Prototype Pollution is possible in immutable via the mergeDeep(), mergeDeepWith(), merge(), Map.toJS(), and Map.toObject() APIs. This issue has been patched in versions 3.8.3, 4.3.7, and 5.1.5.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)1%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products we track (2)
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Additional information
- NVD record
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-wf6x-7x77-mvgwAdvisory
- https://access.redhat.com/errata/RHSA-2026:11070Advisory
- https://access.redhat.com/errata/RHSA-2026:11217Advisory
- https://access.redhat.com/errata/RHSA-2026:11414Advisory
- https://access.redhat.com/errata/RHSA-2026:11858Advisory
- https://github.com/immutable-js/immutable-js/releases/tag/v3.8.3
- https://github.com/immutable-js/immutable-js/releases/tag/v4.3.8
- https://github.com/immutable-js/immutable-js/releases/tag/v5.1.5