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CVE-2026-29063

HIGH CVSS 4.0: 8.7 EPSS 0.21%
Updated Apr 17, 2026
Immutable-Js
Parameter Value
CVSS 8.7 (HIGH)
Affected Versions 3.0.0 — 5.1.5
Fixed In 3.8.3
Type CWE-1321 (Prototype Pollution)
Vendor Immutable-Js
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 3

Configuration From (including) Up to (excluding)
Immutable-Js Immutable
cpe:2.3:a:immutable-js:immutable:*:*:*:*:*:node.js:*:*
3.0.0 3.8.3
Immutable-Js Immutable
cpe:2.3:a:immutable-js:immutable:*:*:*:*:*:node.js:*:*
4.0.0 4.3.7
Immutable-Js Immutable
cpe:2.3:a:immutable-js:immutable:*:*:*:*:*:node.js:*:*
5.0.0 5.1.5