Public proof of conceptFix available

CVE-2026-4800

Q: Is CVE-2026-4800 actively exploited?

Active exploitation of CVE-2026-4800 has not been confirmed. Its EPSS score was 2.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2026-4800?

CVE-2026-4800 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2026-03-31
Fixed in4.18.0
WeaknessCWE-94

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names, and both paths flow into the same Function() constructor sink. When an application passes untrusted input as options.imports key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time. Additionally, _.template uses assignInWith to merge imports, which enumerates inherited properties via for..in, so if Object.prototype has been polluted by another vector the polluted keys are copied into the imports object and passed to Function(). The issue is fixed in 4.18.1 for lodash, lodash-es, lodash-amd, and lodash.template. As a workaround, do not pass untrusted input as key names in options.imports; use only developer-controlled, static key names.

Timeline

dates in UTC

2026-03-3120:16CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-4800?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-4800?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Lodash

Branch	Affected	Fixed in	Source
4.x	≥ 4.0.0, < 4.18.0	4.18.0	NVD

Lodash lodash-amd

Branch	Affected	Fixed in	Source
4.x	≥ 4.0.0, < 4.18.0	4.18.0	NVD

Lodash lodash-es

Branch	Affected	Fixed in	Source
4.x	≥ 4.0.0, < 4.18.0	4.18.0	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

RHSA-2026:83622 Red Hat Product Security68 products fixed
Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.17.28 security, enhancement & bug fix update
RHSA-2026:83619 Red Hat Product Security64 products fixed
Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.16.36 security, enhancement & bug fix update
RHSA-2026:83598 Red Hat Product Security1 product fixed
Red Hat Security Advisory: RHTAS 1.4.4 - Red Hat Trusted Artifact Signer Release
RHSA-2026:59833 Red Hat Product Security1 product fixed
Red Hat Security Advisory: OpenShift Container Platform 4.12.97 bug fix and security update
RHSA-2026:60023 Red Hat Product Security4 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.17.57 bug fix and security update
RHSA-2026:56854 Red Hat Product Security4 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.16.69 bug fix and security update

43 more advisories

Full record on NVD

Fix

Update Lodash to 4.18.0
Vendor fix Red Hat Product Security RHSA-2026:83622 · 68 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.17/html/updating_openshift_data_foundation/updating-ocs-…
Vendor fix Red Hat Product Security RHSA-2026:83619 · 64 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.16/html/updating_openshift_data_foundation/updating-ocs-…
Vendor fix Red Hat Product Security RHSA-2026:83598 · 1 productRed Hat Trusted Artifact Signer simplifies cryptographic signing and verifying of software artifacts such as container images, binaries and source code changes. It is a self-managed on-premise deployment of the Sigstore project available at https://sigstore.dev Platform Engineers, Software Develop…
Vendor fix Red Hat Product Security RHSA-2026:59833 · 1 productFor OpenShift Container Platform 4.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:60023 · 4 productsFor OpenShift Container Platform 4.17 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:56854 · 4 productsFor OpenShift Container Platform 4.16 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…

Detection

read 2026-10-23 19:25 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 2 repositories, unverifiedthrealwinky/CVE-2026-4800-POCSvenLie/next-rep-CVE-2026-4800

Sources

CISA-ADPSSVC decisionnone2026-03-31
OpenCVESSVC decisionnone—
CNACVSS 3.18.1read 2026-10-23
NVDCVSS 3.19.8read 2026-10-23
CNAweakness (CWE)CWE-94read 2026-10-23
FIRST EPSSEPSS score2.6 %2026-10-22
PoC-in-GitHubproof of concept2read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2026-03-31
Last Modified: 2026-10-15
NVD status: Modified

Frequently asked questions

What is CVE-2026-4800?

Is CVE-2026-4800 actively exploited?

Active exploitation of CVE-2026-4800 has not been confirmed. Its EPSS score was 2.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-4800?

CVE-2026-4800 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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