Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 8.7amended

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

CVE-2026-59879GHSA-v56q-mh7h-f735

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (immutable 5.1.8, 4.3.9, 3.8.4), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • npm immutable

    Affected
    >= 5.0.0-beta.1, < 5.1.8>= 4.0.0-rc.1, < 4.3.9< 3.8.4
    Fixed in
    4.3.9, 3.8.4, 5.1.8

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.7 · 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 · score source
EPSS
  • CVE-2026-59879: 0.57% estimated exploitation activity in the next 30 days; percentile 47.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary List#set, List#setSize, List#setIn, List#updateIn (and the functional set / setIn / updateIn) mishandle an index or size in the range 2 30, 2 31): - On an empty List the operation enters an uncatchable infinite loop (a tight CPU spin; a surrounding try/catch never regains control). Only killing the worker recovers it. - On a populated List (≥ 32 elements — i.e. any array of ≥ 32 items turned into a List by fromJS) the loop allocates without bound → heap exhaustion → the process aborts (SIGABRT, exit 134, or kernel OOM-kill 137). A real crash, not a recoverable error. The index may be a numeric string, so it can come straight from a request body, URL, or key-path. A single small unauthenticated request is enough. There is also a companion silent data-corruption issue in setSize: Impact Availability only. A reachable configuration is any endpoint that routes untrusted input into a List index or a setIn/updateIn key-path — which the extremely common state = fromJS(body);…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-v56q-mh7h-f735

  2. Revision 2 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 1 · created ·

    Published from osv record GHSA-v56q-mh7h-f735

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-59879

Advisory: Immutable.js `List` 32-bit trie overflow → unrecoverable DoS
IDs: CVE-2026-59879, GHSA-v56q-mh7h-f735
Record: https://patchnext.com/advisories/cve-2026-59879 (revision 3, source checked 26 Oct 2026, 13:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: immutable 5.1.8, 4.3.9, 3.8.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm immutable: affected >= 5.0.0-beta.1, < 5.1.8; >= 4.0.0-rc.1, < 4.3.9; < 3.8.4; fixed in 4.3.9, 3.8.4, 5.1.8

## Suggested inspection (read-only)
- `npm ls immutable --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on immutable.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-v56q-mh7h-f735 (OSV record GHSA-v56q-mh7h-f735 lists affected ranges: npm immutable >=4.0.0-rc.1 =5.0.0-beta.1 =0 <3.8.4 (fixed))
- Verified: https://github.com/advisories/GHSA-v56q-mh7h-f735 (GitHub-reviewed advisory GHSA-v56q-mh7h-f735 lists affected ranges: npm immutable >=5.0.0-beta.1 =4.0.0-rc.1 =0 <3.8.4)

Commands are suggestions: review each one before running it.

Loading voting…