CVE-2026-4800

Aliases:GHSA-r5fr-rjxr-66jc
Advisory lineage Upstream: 0 Downstream: 18
Analyzed
Published: 31 Mar 2026, 19:25
Last modified:09 Jul 2026, 12:09

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.8 CRITICAL
v3.1 (nvd)
EPSS Score
1.74% LOW
2% probability +0.71%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

31 Mar 2026, 19:25
Published
Vulnerability first disclosed
09 Jul 2026, 12:09
Last Modified
Vulnerability information updated

Description

Impact: The fix for CVE-2021-23337 (https://github.com/advisories/GHSA-35jh-r3h4-6jhm) 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. 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. If Object.prototype has been polluted by any other vector, the polluted keys are copied into the imports object and passed to Function(). Patches: Users should upgrade to version 4.18.0. Workarounds: Do not pass untrusted input as key names in options.imports. Only use developer-controlled, static key names.

CVSS Metrics

  • v3.1•HIGH•Score: 8.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
  • v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 1.74%• Percentile: 75%

Techniques & Countermeasures

  • CWE-94•Improper Control of Generation of Code ('Code Injection')

    The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Affected Systems

  • lodash•lodash

    < 4.17.21 | ≥ 4.0.0, < 4.18.0

  • lodash•lodash-amd

    ≥ 4.0.0, < 4.18.0

  • lodash•lodash-es

    < 4.17.21 | ≥ 4.0.0, < 4.18.0

  • lodash•lodash-rails

    < 4.17.21

  • lodash•lodash.template

    ≤ 4.5.0 | ≥ 4.0.0, < 4.18.0

  • Npm•lodash

    ≥ 4.0.0, < 4.18.0

  • Npm•lodash-amd

    ≥ 4.0.0, < 4.18.0

  • Npm•lodash-es

    ≥ 4.0.0, < 4.18.0

  • Npm•lodash.template

    ≥ 4.0.0, < 4.18.0

References (64)