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8.3
Immutable.js: Prototype Pollution in Merge Functions
UBUNTU-CVE-2026-29063
Summary
If you use Immutable.js versions 3.8.2 and below, 4.3.6 and below, or 5.1.4 and below, an attacker could manipulate your data by exploiting a vulnerability in the merge functions. This could lead to sensitive data being compromised. Update to version 3.8.3, 4.3.7, or 5.1.5 or later to fix the issue.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| canonical | node-immutable | All versions | – |
| canonical | node-immutable | All versions | – |
| canonical | node-immutable | All versions | – |
| canonical | node-immutable | All versions | – |
Original title
Immutable.js provides many Persistent Immutable data structures. Prior to versions 3.8.3, 4.3.7, and 5.1.5, Prototype Pollution is possible in immutable via the mergeDeep(), mergeDeepWith(), merge(...
Original description
Immutable.js provides many Persistent Immutable data structures. Prior to versions 3.8.3, 4.3.7, and 5.1.5, Prototype Pollution is possible in immutable via the mergeDeep(), mergeDeepWith(), merge(), Map.toJS(), and Map.toObject() APIs. This issue has been patched in versions 3.8.3, 4.3.7, and 5.1.5.
osv CVSS4.0
8.3
- https://ubuntu.com/security/CVE-2026-29063 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2026-29063 Third Party Advisory
- https://github.com/immutable-js/immutable-js/releases/tag/v3.8.3 Third Party Advisory
- https://github.com/immutable-js/immutable-js/releases/tag/v4.3.8 Third Party Advisory
- https://github.com/immutable-js/immutable-js/releases/tag/v5.1.5 Third Party Advisory
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-wf6x-7x77-... Third Party Advisory
Published: 9 Mar 2026 · Updated: 13 Mar 2026 · First seen: 10 Mar 2026