GHSA-2cf5-4w76-r9qv

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    GHSA-2cf5-4w76-r9qv

    Published: 4 Sept 2020Last Modified: 10 Sept 2026

    Summary: Arbitrary Code Execution in handlebars

    Details: Versions of `handlebars` prior to 3.0.8 or 4.5.2 are vulnerable to Arbitrary Code Execution. The package's lookup helper fails to properly validate templates, allowing attackers to submit templates that execute arbitrary JavaScript in the system. It can be used to run arbitrary code in a server processing Handlebars templates or on a victim's browser (effectively serving as Cross-Site Scripting). The following template can be used to demonstrate the vulnerability: ```{{#with "constructor"}} {{#with split as |a|}} {{pop (push "alert('Vulnerable Handlebars JS');")}} {{#with (concat (lookup join (slice 0 1)))}} {{#each (slice 2 3)}} {{#with (apply 0 a)}} {{.}} {{/with}} {{/each}} {{/with}} {{/with}} {{/with}}``` ## Recommendation Upgrade to version 3.0.8, 4.5.2 or later.

    References: https://www.npmjs.com/advisories/1316

    Affected packages

    Package

    Name: handlebars

    Purl: pkg:npm/handlebars

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -3.0.8

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    GHSA-2cf5-4w76-r9qv | CVE-DB