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

> CVE-2026-59880: Immutable.js: Hash-collision algorithmic complexity denial of service in Immutable.Map/Set. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-59880
Last updated: 2026-07-10T18:49:51Z

- Published: 2026-07-08 15:44 UTC · Updated: 2026-07-10 18:49 UTC · Assigner: GitHub\_M
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 0.66%, 52th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-407

## 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.

## Affected vendors and products

- immutable-js: immutable-js

## Tracked companies

- [Confluence](https://rewindex.com/company/confluence.md)
- [Jira](https://rewindex.com/company/jira.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-59880)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-59880)
- [https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b](https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b)
- [https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f](https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f)
- [https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9](https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9)
- [https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8](https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8)
- [https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r](https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-59880 · Markdown: https://rewindex.com/cve/CVE-2026-59880.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-59880 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:10:42.296Z