8.7
High
CVE-2026-59879 Immutable.js provides many Persistent Immutable data structures
Description
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| immutable-js 5.0 | 5.0.0-beta.1 → < 5.1.8 | 5.1.8 |
| immutable-js 4.3 | earliest → < 4.3.9 | 4.3.9 |