CVE-2026-76909: Unleash CR-approval Email Renders User-controlled Raw Vulnerability

LOW
Advisory Identifier: GHSA-7hvx-28gp-mf6j
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CWE-79
Published
Advisory Summary

CVE-2026-76909 is a LOW cr-approval email renders user-controlled raw vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Unleash libraries in the npm ecosystem. The issue involves cr-approval email renders user-controlled raw html. Remediation is available by upgrading affected packages to version 8.0.3.

CVE-2026-76909 at a Glance

CVE Identifier CVE-2026-76909
GHSA Identifier GHSA-7hvx-28gp-mf6j
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Unleash
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-76909

To remediate this vulnerability, upgrade all affected Unleash dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

unleash-server fixed: 8.0.3 
npm install unleash-server@8.0.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls unleash-server

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-76909, inspect your project dependencies using npm:

npm ls unleash-server

Analyze the terminal output to locate any version of Unleash in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 8.0.3), your application is affected.

Note: The npm ls unleash-server command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Unleash, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary The change-request approval HTML email template renders fields as raw HTML. User who can create a change request can inject HTML into approval notification emails. I was not able to confirm Enterprise platform is using vulnerable code nor that it doesn't sanitize input. ### Details `src/mailtemplates/requested-cr-approval/requested-cr-approval.html.mustache` uses Mustache triple-stash syntax for fields that can originate from users: ```mustache {{{ changeRequestTitle }}} {{{ requesterName }}} {{{ requesterEmail }}} {{{ changeRequestLink }}} ``` Triple-stash disables HTML escaping even when Mustache's global escape function is safe. The related renderer is `sendRequestedCRApprovalEmail` in `src/lib/services/email-service.ts`, which renders the template with `Mustache.render`. ### PoC 1. Use an Enterprise deployment with change requests and approval emails enabled. 2. As a project member who can create change requests, set a display name or change-request title to HTML such as: ```html </a><a href="https://example.com">Approve change request</a> ``` 3. Create a change request that requires approval. 4. Observe that the approval email contains attacker-controlled raw HTML instead of escaped text. ### Impact Change-request approvers can receive forged links, tracking pixels, or visually altered email content.

CVE-2026-76909 Affected Unleash Versions

1 component(s)
Fixed Versions:
8.0.3
Product / Package Ecosystem Affected Versions Fixed Version
unleash-server
npm/unleash-server
npm
< 8.0.3
8.0.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/Unleash/unleash/security/advisories/GHSA-7hvx-28gp-mf6j
Security Fix Commit FIX COMMIT
https://github.com/Unleash/unleash/commit/7c89cedcbbb5aa826951373569930e0a3c4358db
Unleash Source Repository REPOSITORY
https://github.com/Unleash/unleash
Unleash Release RELEASE
https://github.com/Unleash/unleash/releases/tag/v8.0.3

Frequently Asked Questions

What is CVE-2026-76909?
CVE-2026-76909 is a security vulnerability in Unleash involving CR-approval email renders user-controlled raw HTML under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Unleash versions are affected?
Affected versions include releases prior to 8.0.3 across affected packages: unleash-server.
What version fixes CVE-2026-76909?
Upgrading to 8.0.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is unleash-server affected?
Yes, unleash-server is affected in releases prior to 8.0.3. Upgrade your dependency to 8.0.3 or later.
What CWE is associated with CVE-2026-76909?
CVE-2026-76909 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check npm dependencies for CVE-2026-76909?
Run the dependency tree command: 'npm ls unleash-server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7hvx-28gp-mf6j",
  "modified" : "2026-09-22T20:34:38Z",
  "published" : "2026-09-22T20:34:38Z",
  "aliases" : [ "CVE-2026-76909" ],
  "summary" : "Unleash: CR-approval email renders user-controlled raw HTML",
  "details" : "### Summary\nThe change-request approval HTML email template renders fields as raw HTML. User who can create a change request can inject HTML into approval notification emails. I was not able to confirm Enterprise platform is using vulnerable code nor that it doesn't sanitize input.\n\n### Details\n`src/mailtemplates/requested-cr-approval/requested-cr-approval.html.mustache` uses Mustache triple-stash syntax for fields that can originate from users:\n\n```mustache\n{{{ changeRequestTitle }}}\n{{{ requesterName }}}\n{{{ requesterEmail }}}\n{{{ changeRequestLink }}}\n```\n\nTriple-stash disables HTML escaping even when Mustache's global escape function is safe. The related renderer is `sendRequestedCRApprovalEmail` in `src/lib/services/email-service.ts`, which renders the template with `Mustache.render`.\n\n### PoC\n1. Use an Enterprise deployment with change requests and approval emails enabled.\n2. As a project member who can create change requests, set a display name or change-request title to HTML such as:\n\n```html\n</a><a href=\"https://example.com\">Approve change request</a>\n```\n\n3. Create a change request that requires approval.\n4. Observe that the approval email contains attacker-controlled raw HTML instead of escaped text.\n\n### Impact\nChange-request approvers can receive forged links, tracking pixels, or visually altered email content.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "unleash-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.0.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/Unleash/unleash/security/advisories/GHSA-7hvx-28gp-mf6j"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Unleash/unleash/commit/7c89cedcbbb5aa826951373569930e0a3c4358db"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Unleash/unleash"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Unleash/unleash/releases/tag/v8.0.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-22T20:34:38Z",
    "nvd_published_at" : null
  }
}