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Vulnerabilities

Vulnerability · CVE-2026-4800

lodash vulnerable to Code Injection via imports key names

Published Mar 31, 2026 · catalog updated Oct 17, 2026 · Red Hat

Check if you run it

No confirmed exploitation is on record for CVE-2026-4800. EPSS is 2.62%. Act only if a listed version of Red Hat is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
2.62%
Remediation
Advisory link
Affected products
cpe lodash/lodash · cpe lodash/lodash-amd · cpe lodash/lodash-es · cpe lodash/lodash.template · npm lodash · npm lodash-amd

### Impact The fix for [CVE-2021-23337](https://github.com/advisories/GHSA-35jh-r3h4-6jhm) added validation for the option in but did not apply the same validation to key names. Both paths flow into the same constructor sink. When an application passes untrusted input as key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time. Additionally, uses to merge imports, which enumerates inherited properties via . If has been polluted by any other vector, the polluted keys are copied into the imports object and passed to . ### Patches Users should upgrade to version 4.18.0. The fix applies two changes: 1. Validate against the existing regex (same check already used for the option) 2. Replace with when merging imports, so only own properties are enumerated ### Workarounds Do not pass untrusted input as key names in . Only use developer-controlled, static key names.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe lodash/lodashversion unspecified
  • cpe lodash/lodash-amdversion unspecified
  • cpe lodash/lodash-esversion unspecified
  • cpe lodash/lodash.templateversion unspecified
  • npm lodash4.0.0 → 4.18.0
  • npm lodash-amd4.0.0 → 4.18.0
  • npm lodash-es4.0.0 → 4.18.0
  • npm lodash.template4.0.0 → 4.18.0
  • vendor lodash lodashversion unspecified
  • vendor lodash lodash-amdversion unspecified
  • vendor lodash lodash-esversion unspecified
  • vendor lodash lodash.templateversion unspecified

How to fix CVE-2026-4800

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4800. EPSS is 2.62%. Act only if a listed version of Red Hat is installed.

Which versions are affected?

Compare what you have installed with 4.0.0 → 4.18.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-94: Code Injection. EPSS 2.62%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 31, 2026 · NIST NVD

    Detected

    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. Add

  2. Oct 15, 2026 · NIST NVD

    Updated

    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. Add

  3. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lodash fixed in 4.18.0; lodash-es fixed in 4.18.0; lodash-amd fixed in 4.18.0; lodash.template fixed in 4.18.0

  4. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lodash fixed in 4.18.0

  5. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lodash-es fixed in 4.18.0

  6. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lodash-amd fixed in 4.18.0

  7. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lodash.template fixed in 4.18.0

  8. Oct 17, 2026 · GitHub Advisory Database

    Updated

    ### Impact The fix for [CVE-2021-23337](https://github.com/advisories/GHSA-35jh-r3h4-6jhm) added validation for the option in but did not apply the same validation to key names. Both paths flow into the same constructor sink. When an application passes untrusted input as key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time. Additi

Sources

  • CIRCL Vulnerability LookupVulnerability recordCVE-2026-4800

    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 n

    vulnerability.circl.lu
  • CSAF AdvisoriesVendor advisoryRHSA-2026:9742:CVE-2026-4800

    A flaw was found in lodash. 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. Both paths flow into the same Function() constructor sink. Additionally, _.template uses assignInWith

    security.access.redhat.com
  • CVE.orgVulnerability recordCVE-2026-4800

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4800

    30-day exploitation probability 2.6%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-r5fr-rjxr-66jc

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • NIST NVDVulnerability recordCVE-2026-4800

    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 n

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryGHSA-r5fr-rjxr-66jc

    lodash vulnerable to Code Injection via imports key names

    osv.dev

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.