Security readout for executives and security teams
Plain-English summary
CVE-2021-32818 affects haml-coffee, a JavaScript templating package. If an application lets user-controlled request data influence haml-coffee render options, attackers may reach remote code execution. The same configuration pollution can disable HTML escaping and cause reflected XSS. The bundle states no fix was available at publication.
Executive priority
Treat as high priority where haml-coffee is used in externally reachable web applications. Business urgency depends on whether user-controlled request data reaches template rendering. If that pattern exists, prioritize remediation or replacement planning because sources do not name a fixed version.
Technical view
haml-coffee mixes template data and engine configuration through the Express render API. User-controlled objects passed into rendering can override HTML helper functions, creating RCE risk. Control over escapeHtml can disable sanitization and expose reflected XSS in downstream applications. Affected versions are listed as <= 1.14.1.
Likely exposure
Exposure is most likely in Node.js applications using haml-coffee with Express rendering where request-derived objects are passed into templates or render configuration. Projects merely having the package installed are lower risk unless vulnerable render patterns are present.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. CVSS indicates network attack vector, high complexity, low privileges, required user interaction, changed scope, and high confidentiality and integrity impact.
Researcher notes
The key condition is configuration pollution through Express render integration, not just generic template input. Validate data-flow into render options, helper override capability, and escapeHtml control. Keep analysis source-grounded; no cited source confirms active exploitation.
Mitigation direction
- Inventory haml-coffee usage and affected versions in dependency manifests and lockfiles.
- Do not pass user-controlled request objects into haml-coffee render options.
- Use strict allowlists for render locals and template configuration fields.
- Prevent user influence over escapeHtml or HTML helper configuration.
- Check vendor advisory and package guidance because no fix is named in the sources.
Validation and detection
- Confirm whether haml-coffee <= 1.14.1 is present in production dependencies.
- Review Express render calls for request-derived objects or merged configuration.
- Verify render configuration is built from trusted, explicit fields only.
- Check XSS regression coverage for reflected template input escaping.
- Document any compensating controls or migration decision for vulnerability management.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-32818 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N1.35.8Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.7HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://securitylab.github.com/advisories/GHSL-2021-025-haml-coffee/CVE reference · x_refsource_CONFIRM
- https://www.npmjs.com/package/haml-coffeeCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.