CVE-2026-59880
What it is
Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, Immutable.Map and Immutable.Set keep keys that share the same 32-bit hash in a HashCollisionNode collision bucket that is scanned linearly, allowing an attacker who controls keys inserted into a Map, such as through Immutable.Map(obj), Immutable.fromJS(obj), state.merge(userObject), or mergeDeep, to craft many colliding keys and degrade insertion and lookup to consume disproportionate CPU. This issue is fixed in versions 4.3.9 and 5.1.8.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Exploit odds
- 0.7% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.7% in the next 30 days (EPSS).
- Severity: 8.7 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.7% · EPSS, next 30 days
- Weakness
- CWE-407
- Record status
- Analyzed
Affected
- immutable-js Immutable < 4.3.9
- immutable-js Immutable < 5.1.8
Attack profile CVSS 4.0 · 8.7
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw 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/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
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-59880.md and follow it. Check whether this project is affected by CVE-2026-59880. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b
- https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f
- https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9
- https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r
References
- https://github.com/immutable-js/immutable-js/commit/3dd7e5655012597a41873e328bf9142a8901527b
- https://github.com/immutable-js/immutable-js/commit/e51d49fc612ded5ec4dfb94ff294d22074269b0f
- https://github.com/immutable-js/immutable-js/releases/tag/v4.3.9
- https://github.com/immutable-js/immutable-js/releases/tag/v5.1.8
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-xvcm-6775-5m9r