High 8.7Published Mar 6, 2026

CVE-2026-29063Immutable.js: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in immutable

Updated under an hour ago (Oct 27, 2026, 2:23 AM ET)

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It affects immutable-js and 29 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for immutable-js

Exploited in the last 30 days

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.

CVSS: 8.7 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-1321, CWE-915
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Modified
Record last updated: Sep 10, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

immutable-js immutable-js immutable_js:immutable_js (from the name)	before 3.8.3; before 4.3.7; before 5.1.5	CNA record
Red Hat Cluster Observability Operator 1.5.0 redhat:cluster_observability_operator	from 1782839279 not affected	CISA ADP
Red Hat Migration Toolkit for Virtualization 2.1 redhat:migration_toolkit_virtualization	from 1779139872 not affected	CISA ADP
Red Hat multicluster engine for Kubernetes 2.1 redhat:multicluster_engine	from 1777128790 not affected	CISA ADP
Red Hat Network Observability (NETOBSERV) 1.11.0 redhat:network_observ_optr	from 1774431617 not affected	CISA ADP
Red Hat Red Hat Advanced Cluster Management for Kubernetes 2.14 redhat:acm	from 1783451729 not affected	CISA ADP
Red Hat Red Hat Advanced Cluster Security 4.8 redhat:advanced_cluster_security	from 1777307791 not affected	CISA ADP
Red Hat Red Hat Developer Hub 1.8 redhat:rhdh	from 1776784286 not affected	CISA ADP
Red Hat Red Hat Discovery 2 redhat:discovery	from 1775675922 not affected	CISA ADP
Red Hat Red Hat Edge Manager 1.0 redhat:edge_manager	from 1783502765 not affected	CISA ADP
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References

References

https://github.com/immutable-js/immutable-js/security/advisories/GHSA-wf6x-7x77-mvgw	x-refsource-confirm, exploit, vendor-advisory
https://github.com/immutable-js/immutable-js/releases/tag/v3.8.3	x-refsource-misc, release-notes
https://github.com/immutable-js/immutable-js/releases/tag/v4.3.8	x-refsource-misc, release-notes
https://github.com/immutable-js/immutable-js/releases/tag/v5.1.5	x-refsource-misc, release-notes
https://access.redhat.com/errata/RHSA-2026:11070
https://access.redhat.com/errata/RHSA-2026:11217
https://access.redhat.com/errata/RHSA-2026:11414
https://access.redhat.com/errata/RHSA-2026:11858
https://access.redhat.com/errata/RHSA-2026:11916
https://access.redhat.com/errata/RHSA-2026:12118
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.