CVE-2026-59880

HIGH

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

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-59880. PoCs published by nvth.

AI-analyzed exploit summary The repository contains only a README.md and LICENSE file with no exploit code, technical details, or functional PoC. It references an external write-up but does not include any substantive content itself.

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.

Exploits (1)

nomisec STUB
by nvth · poc
https://github.com/nvth/cve-2026-59880

The repository contains only a README.md and LICENSE file with no exploit code, technical details, or functional PoC. It references an external write-up but does not include any substantive content itself.

Classification
Stub 95%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: unspecified
No auth needed
mistral-large-3 · analyzed Jul 24, 2026 Full analysis →

Scores

CVSS v3 7.5
EPSS 0.0043
EPSS Percentile 35.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-407
Status published
Products (5)
immutable-js/immutable < 4.3.9
immutable-js/immutable-js < 4.3.9
immutable-js/immutable-js >= 5.0.0-beta.1, < 5.1.8
npm/immutable 0 - 4.3.9npm
npm/immutable 5.0.0-beta.1 - 5.1.8npm
Published Jul 08, 2026
Tracked Since Jul 08, 2026