Insecure template handling in haml-coffee

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.7 · CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS

• CVE-2021-32818: 0.70% estimated exploitation activity in the next 30 days; percentile 53.21 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

haml-coffee is a JavaScript templating solution. haml-coffee mixes pure template data with engine configuration options through the Express render API. More specifically, haml-coffee supports overriding a series of HTML helper functions through its configuration options. A vulnerable application that passes user controlled request objects to the haml-coffee template engine may introduce RCE vulnerabilities. Additionally control over the escapeHtml parameter through template configuration pollution ensures that haml-coffee would not sanitize template inputs that may result in reflected Cross Site Scripting attacks against downstream applications. There is currently no fix for these issues as of the publication of this CVE. The latest version of haml-coffee is currently 1.14.1. For complete details refer to the referenced GHSL-2021-025.

Published by the source

17 May 2021, 20:58 UTC

Last modified by the source

8 Nov 2023, 04:06 UTC

Source last checked

26 Oct 2026, 12:20 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m7mf-vm62-7x3q

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-m7mf-vm62-7x3q

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# Patch Next advisory brief: CVE-2021-32818

Advisory: Insecure template handling in haml-coffee
IDs: CVE-2021-32818, GHSA-m7mf-vm62-7x3q
Record: https://patchnext.com/advisories/cve-2021-32818 (revision 2, source checked 26 Oct 2026, 12:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm haml-coffee: affected <= 1.14.1

## Suggested inspection (read-only)
- `npm ls haml-coffee --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on haml-coffee.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-m7mf-vm62-7x3q (OSV record GHSA-m7mf-vm62-7x3q lists affected ranges: npm haml-coffee >=0 <=1.14.1)
- Verified: https://github.com/advisories/GHSA-m7mf-vm62-7x3q (GitHub-reviewed advisory GHSA-m7mf-vm62-7x3q lists affected ranges: npm haml-coffee >=0 <=1.14.1)

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