8.6

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2021-32820

CVE-2021-32820: Insecure template handling in Express-handlebars

Express-handlebars is a Handlebars view engine for Express. Express-handlebars mixes pure template data with engine configuration options through the Express render API. More specifically, the layout parameter may trigger file disclosure vulnerabilities in downstream applications. This potential vulnerability is somewhat restricted in that only files with existing extentions (i.e. file.extension) can be included, files that lack an extension will have .handlebars appended to them. For complete details refer to the referenced GHSL-2021-018 report. Notes in documentation have been added to help users avoid this potential information exposure vulnerability.

A fix is discussed in https://github.com/express-handlebars/express-handlebars/pull/163

(GitHub Advisory)

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CVE-2021-32820

CVE-2021-32820:

8.6

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
express-handlebars	npm	< 5.3.1	5.3.1

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability stems from Express-handlebars' handling of the 'layout' parameter in the render API. The renderView function accepts engine configuration options mixed with template data, and when user-controlled input (e.g., req.query) is passed to res.render(), attackers can manipulate the 'layout' parameter to access arbitrary files. The security advisory explicitly identifies this parameter as the injection vector, and the documentation warnings confirm the pattern of unsafe API usage. While the exact file path isn't visible in provided resources, the renderView function is the primary entry point for template rendering and layout handling in Express-handlebars.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

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WAF Protection Rules

WAF Rule

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Reasoning

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