PT-2026-56499 · Immutable Js · Immutable-Js

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-59880

NVD

CVSS v4.0

8.7

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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.

Exploit

Fix

Weakness Enumeration

CWE-407

Related Identifiers

CVE-2026-59880

Affected Products

Immutable-Js

References · 6

• 🔥 https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-59880 · Security Note
• https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9 · Note
• https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8 · Note
• https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f · Note
• https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b · Note