CVE-2026-59880

Immutable.js: Hash-collision algorithmic complexity denial of service in Immutable.Map/Set

Published Jul 8, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, Immutable.Map and Immutable.Set keep keys that share the same 32-bit hash in a HashCollisionNode collision bucket that is scanned linearly, allowing an attacker who controls keys inserted into a Map, such as through Immutable.Map(obj), Immutable.fromJS(obj), state.merge(userObject), or mergeDeep, to craft many colliding keys and degrade insertion and lookup to consume disproportionate CPU. This issue is fixed in versions 4.3.9 and 5.1.8.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xvcm-6775-5m9r Immutable: Hash-collision algorithmic complexity denial of service in Immutable.Map/Set
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Immutable-js
Immutable-js immutable-js
Vendors & Products Immutable-js
Immutable-js immutable-js
Type Values Removed Values Added
Description Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, Immutable.Map and Immutable.Set keep keys that share the same 32-bit hash in a HashCollisionNode collision bucket that is scanned linearly, allowing an attacker who controls keys inserted into a Map, such as through Immutable.Map(obj), Immutable.fromJS(obj), state.merge(userObject), or mergeDeep, to craft many colliding keys and degrade insertion and lookup to consume disproportionate CPU. This issue is fixed in versions 4.3.9 and 5.1.8.
Title Immutable.js: Hash-collision algorithmic complexity denial of service in Immutable.Map/Set
Weaknesses CWE-407
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 8, 2026, 4:13 PM
Reserved
Jul 7, 2026, 4:40 PM
Status
Analyzed
Published
Jul 8, 2026, 4:16 PM
Modified
Jul 10, 2026, 6:49 PM