# immutable (npm) vulnerabilities

3 known vulnerabilities (3 high), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: 5.1.9 (Jun 29, 2026): no advisory affects it
- Newest unaffected release: 5.1.9 (Jun 29, 2026), the latest release
- Weekly downloads: 58.1M
- Dependents: 23.1K
- Releases: 123 since 0.8.0 (Mar 27, 2013)
- Registry: https://www.npmjs.com/package/immutable
- Releases read: Nov 8, 2026

## Version timeline

Affected versions per advisory, in version order:

- CVE-2026-59879: 0.8.0-SNAPSHOT to 3.8.3 (3.8.4 is outside it); 4.0.0-rc.1 to 4.3.8 (4.3.9 is outside it); 5.0.0-beta.1 to 5.1.7 (5.1.8 is outside it)
- CVE-2026-59880: 0.8.0-SNAPSHOT to 3.8.3 (3.8.4 is outside it); 4.0.0-rc.1 to 4.3.8 (4.3.9 is outside it); 5.0.0-beta.1 to 5.1.7 (5.1.8 is outside it)
- CVE-2026-29063: 0.8.0-SNAPSHOT to 3.8.2 (3.8.3 is outside it); 4.0.0-rc.1 to 4.3.7 (4.3.8 is outside it); 5.0.0 to 5.1.4 (5.1.5 is outside it)

## Advisories (3)

### [CVE-2026-59879](https://cve.now/CVE-2026-59879): Immutable.js \`List\` 32-bit trie overflow → unrecoverable DoS

- Severity: High 8.7
- Published: Jul 8, 2026
- Affected: from 4.0.0-rc.1, fixed in 4.3.9; from 5.0.0-beta.1, fixed in 5.1.8; fixed in 3.8.4.
- Fixed in 3.8.4 (released Aug 14, 2026, 37 days after disclosure), 4.3.9 (released Jun 25, 2026, 13 days before disclosure) and 5.1.8 (released Jun 25, 2026, 13 days before disclosure).
- The latest release, 5.1.9, is not affected.
- 51% of immutable downloads last week were affected versions (34.7M).

### [CVE-2026-59880](https://cve.now/CVE-2026-59880): Immutable.js: Hash-collision algorithmic complexity denial of service in Immutable.Map/Set

- Severity: High 8.7
- Published: Jul 8, 2026
- Affected: from 4.0.0-beta.1, fixed in 4.3.9; from 5.0.0-beta.1, fixed in 5.1.8; fixed in 3.8.4.
- Fixed in 3.8.4 (released Aug 14, 2026, 37 days after disclosure), 4.3.9 (released Jun 25, 2026, 13 days before disclosure) and 5.1.8 (released Jun 25, 2026, 13 days before disclosure).
- The latest release, 5.1.9, is not affected.
- 51% of immutable downloads last week were affected versions (34.7M).

### [CVE-2026-29063](https://cve.now/CVE-2026-29063): Immutable.js: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in immutable

- Severity: High 8.7
- Published: Mar 6, 2026
- Affected: from 4.0.0-rc.1, fixed in 4.3.8; from 5.0.0, fixed in 5.1.5; fixed in 3.8.3.
- Fixed in 3.8.3 (released Mar 6, 2026, the day of disclosure), 4.3.8 (released Mar 3, 2026, 3 days before disclosure) and 5.1.5 (released Mar 3, 2026, 3 days before disclosure).
- The latest release, 5.1.9, is not affected.
- 39% of immutable downloads last week were affected versions (26M).

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