October 11, 2026

CVE Watchtower

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CVE-2026-4800NVD

Vulnerability Summary

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.
Severity Level
HIGH(8.1)
Published Date
Mar 31, 2026
Last Modified
Sep 9, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
2.62%Probability
Root Weakness (CWE)
N/A
CVSS v3.1 Base Metrics — Score 8.1 (HIGH)
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Lodash Lodash >= 4.0.0 and < 4.18.0
  • Lodash Lodash-amd >= 4.0.0 and < 4.18.0
  • Lodash Lodash-es >= 4.0.0 and < 4.18.0
  • Lodash Lodash.template >= 4.0.0 and < 4.18.0
Patched Versions
  • Lodash Lodash 4.18.0
  • Lodash Lodash-amd 4.18.0
  • Lodash Lodash-es 4.18.0
  • Lodash Lodash.template 4.18.0
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🎁7-Day Free Trial — Try Pro or Team, no card required.
📧Email Delivery — Threat intel straight to your inbox.
♾️Unlimited Vendors — Track your entire stack.
🚨All New CVEs — Be the first to know.
📈EPSS Spike Alerts — Catch rising risk before it peaks.
🎯Custom EPSS/CVSS — Filter noise, focus on risk.
🛡️Exploit Intel — A 2nd confirmed-exploit signal beyond KEV.
🐙GitHub Issues — Auto-tracked, no duplicates.
📬Weekly Digest — One clean summary, not inbox spam.
🏷️Watchlist Groups — Tag alerts by team (Infra/AppSec/SOC).
💬Webhooks — Slack & Teams integration.
🔀Smart Routing — Critical alerts to one channel, rest to another.
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External References