CVE-2021-32818Public exploitNetwork attack vector

Code execution and reflected XSS via option injection

Published May 14, 2021 · Updated Aug 3, 2024

Template option injection in netzpirat Haml Coffee 1.14.1 and earlier allows remote attackers to execute code or trigger reflected XSS. The Express render adapter mixes template data with engine options, letting request parameters replace customHtmlEscape with executable JavaScript or set escapeHtml to false. Exposure requires a downstream Express application to pass a user-controlled request object directly to the renderer; code runs on the server, while injected script runs in a user's browser.

CVSS severity7.7
High
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Template option injection in netzpirat Haml Coffee 1.14.1 and earlier allows remote attackers to execute code or trigger reflected XSS. The Express render adapter mixes template data with engine options, letting request parameters replace customHtmlEscape with executable JavaScript or set escapeHtml to false. Exposure requires a downstream Express application to pass a user-controlled request object directly to the renderer; code runs on the server, while injected script runs in a user's browser.

The record

CVE
CVE-2021-32818
Published
May 14, 2021
Updated
Aug 3, 2024
Vendor
netzpirat
Product
Haml Coffee
Classifications
CWE-79, T1059.007, T1203
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. May 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 1.14.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

netzpirat · Haml Coffeeversion=<= 1.14.1

Published CVSS scores

7.7GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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