High 8.7Published Jul 8, 2026

CVE-2026-59880Immutable.js: Hash-collision algorithmic complexity denial of service in Immutable.Map/Set

Updated under an hour ago (Oct 26, 2026, 7:23 PM ET)

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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 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.

CVSS: 8.7 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-407
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: Analyzed
Record last updated: Jul 8, 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 4.3.9; from 5.0.0-beta.1, < 5.1.8	CNA record
immutable-js immutable immutable-js:immutable	before 4.3.9; from 5.0.0 before 5.1.8	NVD

References

References

https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r	x-refsource-confirm, exploit, mitigation, vendor-advisory
https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b	x-refsource-misc, patch
https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f	x-refsource-misc, patch
https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9	x-refsource-misc, release-notes
https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8	x-refsource-misc, release-notes

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.