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CVE Record

CVE-2019-19919: Versions of handlebars prior to 4.3.0 are vulnerable to Prototype Pollution leading to Remote Code Execution.

Versions of handlebars prior to 4.3.0 are vulnerable to Prototype Pollution leading to Remote Code Execution. Templates may alter an Object's __proto__ and __defineGetter__ properties, which may allow an attacker to execute arbitrary code through crafted payloads.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Handlebars versions before 4.3.0 can let a malicious template tamper with JavaScript object prototypes. The published description says this can lead to arbitrary code execution through crafted payloads. The main business risk is older JavaScript dependencies in applications that process untrusted or externally influenced templates.

Executive priority

Prioritize remediation where affected handlebars versions run in production or handle untrusted template content. Because the stated impact includes remote code execution, delay should be justified only when inventory proves the vulnerable library is absent or unreachable.

Technical view

CVE-2019-19919 describes prototype pollution in Handlebars before 4.3.0. Templates may modify Object __proto__ and __defineGetter__ properties, with potential remote code execution. The source bundle provides no CVSS, CWE, CPE, or complete product matrix, so exposure must be confirmed from dependency inventories.

Likely exposure

Likely exposure is Node.js or JavaScript applications using handlebars versions before 4.3.0, especially where templates or template inputs are influenced by users, tenants, integrations, or imported content. The bundle does not provide affected CPEs or downstream product names.

Exploitation context

The bundle does not show active exploitation, and KEV is false. It does state that crafted payloads may enable arbitrary code execution, so vulnerable systems should be treated seriously even without confirmed exploitation evidence.

Researcher notes

Evidence is thin: no CVSS, CWE, CPEs, or exploit telemetry are provided. The strongest source-grounded facts are the affected version boundary, prototype pollution mechanism, RCE impact claim, and absence from KEV in the supplied bundle.

Mitigation direction

  • Upgrade handlebars to 4.3.0 or later, following vendor guidance.
  • Check transitive dependencies that may bundle older handlebars versions.
  • Reduce or remove processing of untrusted templates where possible.
  • Review vendor advisories for downstream products using handlebars.

Validation and detection

  • Inventory package-lock, yarn.lock, pnpm-lock, and SBOM entries for handlebars.
  • Confirm deployed runtime artifacts do not contain handlebars before 4.3.0.
  • Identify routes or jobs that process externally supplied templates or content.
  • Run dependency scanning and verify it flags CVE-2019-19919 as resolved.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2019-19919 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.