CVE-2026-59879

What it is

Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, List#set, List#setSize, List#setIn, List#updateIn, and the functional set, setIn, and updateIn mishandle an index or size in the range 2 ** 30 to 2 ** 31 in setListBounds in src/List.js, causing an empty List to enter an uncatchable infinite loop, a populated List to allocate without bound until process abort, or setSize to silently wrap large values. This issue is fixed in versions 4.3.9 and 5.1.8.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-08 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-10 18:48 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.6% in the next 30 days (EPSS).
• Severity: 8.7 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-08 17:17 UTC

Last modified

2026-07-10 18:48 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-190 · Integer overflow

Record status

Analyzed

Affected

• immutable-js Immutable < 4.3.9
• immutable-js Immutable < 5.1.8

Attack profile CVSS 4.0 · 8.7

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-59879.md and follow it. Check whether this project is affected by CVE-2026-59879. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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