Prototype Pollution in lodash

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2019-10744: 5.01% estimated exploitation activity in the next 30 days; percentile 92.25 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Versions of lodash before 4.17.12 are vulnerable to Prototype Pollution. The function defaultsDeep allows a malicious user to modify the prototype of Object via {constructor: {prototype: {...}}} causing the addition or modification of an existing property that will exist on all objects. Recommendation Update to version 4.17.12 or later.

Published by the source

10 Jul 2019, 19:45 UTC

Last modified by the source

10 Sep 2026, 03:47 UTC

Source last checked

26 Oct 2026, 12:37 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jf85-cpcp-j695

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-jf85-cpcp-j695

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# Patch Next advisory brief: CVE-2019-10744

Advisory: Prototype Pollution in lodash
IDs: CVE-2019-10744, GHSA-jf85-cpcp-j695
Record: https://patchnext.com/advisories/cve-2019-10744 (revision 2, source checked 26 Oct 2026, 12:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: lodash.defaultsdeep 4.6.1; lodash-rails 4.17.12; lodash-es 4.17.14; lodash 4.17.12; lodash-amd 4.17.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm lodash.defaultsdeep: affected < 4.6.1; fixed in 4.6.1
- RubyGems lodash-rails: affected < 4.17.12; fixed in 4.17.12
- npm lodash-es: affected < 4.17.14; fixed in 4.17.14
- npm lodash: affected < 4.17.12; fixed in 4.17.12
- npm lodash-amd: affected < 4.17.13; fixed in 4.17.13

## Suggested inspection (read-only)
- `npm ls lodash.defaultsdeep --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- RubyGems lodash-rails: check the installed version with your package manager.
- `npm ls lodash-es --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls lodash --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls lodash-amd --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 lodash.defaultsdeep, lodash-rails, lodash-es, lodash, lodash-amd.
- 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-jf85-cpcp-j695 (OSV record GHSA-jf85-cpcp-j695 lists affected ranges: npm lodash >=0 =0 =0 =0 =0 <4.17.12 (fixed))
- Verified: https://github.com/advisories/GHSA-jf85-cpcp-j695 (GitHub-reviewed advisory GHSA-jf85-cpcp-j695 lists affected ranges: npm lodash >=0 =0 =0 =0 =0 <4.17.12)

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