CVE-2026-59879

Immutable.js `List` 32-bit trie overflow → unrecoverable DoS

HIGH
7.5
CVSS Score
Published: July 8, 2026 at 03:47 PM UTC
Updated: July 10, 2026 at 07:08 PM UTC
2 products affected across 1 vendorImmutableJs Immutable

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.3.95.0.0 ≤ v < 5.1.8
Affected range stops below 4.3.9, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.1.8, so it looks safe — our inference, not a vendor statement
v < 4.3.9v < 5.1.8
Affected range stops below 4.3.9, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.1.8, so it looks safe — our inference, not a vendor statement

References (5)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-190CWE-400CWE-835CWE-1284

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