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.
https://github.com/immutable-js/immutable-js/security/advisories/GHSA-v56q-mh7h-f735
https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8
https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9
https://github.com/immutable-js/immutable-js/commit/f0bc997d8eb9886aff2236635aa210a95a04304a
https://github.com/immutable-js/immutable-js/commit/a1a1ee412dcaa380ab325196283d06594ffe4b84
Published: 2026-07-08
Updated: 2026-07-08
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:P
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: High
Base Score: 8.7
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High