CVE-2026-29063

Name: CVE-2026-29063
Creator: NVD / NIST
Published: 2026-03-06T19:16:21.557+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 0.61%

Last modified Jun 17, 2026

CVE-2026-29063 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. 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. EPSS estimates a 0.61% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.61%

44.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1321

Affected Software

Vendor	Product	Versions
Immutable-Js	Immutable	>= 3.0.0, < 3.8.3
Immutable-Js	Immutable	>= 4.0.0, < 4.3.7
Immutable-Js	Immutable	>= 5.0.0, < 5.1.5

References

https://github.com/immutable-js/immutable-js/releases/tag/v3.8.3Release Notes
https://github.com/immutable-js/immutable-js/releases/tag/v4.3.8Release Notes
https://github.com/immutable-js/immutable-js/releases/tag/v5.1.5Release Notes
https://github.com/immutable-js/immutable-js/security/advisories/GHSA-wf6x-7x77-mvgwExploit, Vendor Advisory

Timeline

Published: Mar 6, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-29063?

How severe is CVE-2026-29063?

CVE-2026-29063 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.61% probability of exploitation in the next 30 days.

How do I fix CVE-2026-29063?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-29063?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST