CVE WatchJul 10, 2026

CVE-2026-59880

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 sh

CVSS

7.5

High

EPSS

0.4%

p29

KEV

—

Exploit Today

0-100

Published: Jul 8, 2026 · Last modified: Jul 10, 2026 · CWE-407

EPSS · 30d

0.3%EPSS · 30 days0.4%

2026-07-092026-07-21

Technical 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.

Official references

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