CVE-2026-59880 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-59880HIGH

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

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   N   N   N   N   N   H    8.7   .0043   36.2     —

AFFECTED
  Product       Versions   Fixed
  immutable-js  < 4.3.9 –  —

TIMELINE
  Jul 7   Reserved by GitHub_M
  Jul 8   EXPLOIT PUBLISHED — CVE-2026-59880 (immutable-js). Public exploit reference added.
  Jul 8   Published (CNA: GitHub_M)

CWE-407 · CNA: GitHub_M · CVSS v4.0 · 5 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
July 7, 2026	Reserved	Reserved by GitHub_M
July 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-59880 (immutable-js). Public exploit reference added.
July 8, 2026	Published	Published (CNA: GitHub_M)

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
immutable-js	immutable-js	—	< 4.3.9	—

Weaknesses

CWE-407

References (5)

https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b [Patch]
https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f [Patch]
https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9 [Release Notes]
https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8 [Release Notes]
https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r [Exploit, Mitigation, Vendor Advisory]

Authoritative record: CVE-2026-59880 at cve.org

Vendors: immutable-js

Weaknesses: CWE-407

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59880 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.