How severe is CVE-2019-19919?

CVE-2019-19919 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-19919 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-19919?

CVE-2019-19919 primarily affects Handlebars.js Project Handlebars.js. In total, 44 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-19919?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2019-19919 published?

CVE-2019-19919 was published on 2019-12-20 and last updated on 2026-06-17.

CVE-2019-19919

CVE-2019-19919 is a critical-severity vulnerability in Handlebars.js Project Handlebars.js with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1321.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1321
Affected product: Handlebars.js Project Handlebars.js
Published: 2019-12-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2019-19919?: 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.
How severe is CVE-2019-19919?: CVE-2019-19919 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-19919 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-19919?: CVE-2019-19919 primarily affects Handlebars.js Project Handlebars.js. In total, 44 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-19919?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-19919 published?: CVE-2019-19919 was published on 2019-12-20 and last updated on 2026-06-17.

References

Affected products (44)

cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.6:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.7:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.8:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.9:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.10:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.11:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.0.12:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.1.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.1.1:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.1.2:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.2.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.2.1:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:1.3.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:2.0.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.1:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.2:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.3:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.4:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.5:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.6:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:3.0.7:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.1:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.2:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.3:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.4:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.5:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.6:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.7:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.8:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.9:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.10:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.11:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.12:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.13:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.0.14:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.1.0:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.1.1:-:*:*:*:node.js:*:*
cpe:2.3:a:handlebars.js_project:handlebars.js:4.1.2:-:*:*:*:node.js:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

103.159.85.123 (ipv4-addr)
89.67.39.124 (ipv4-addr)
89.67.246.166 (ipv4-addr)