GHSA-7HVX-28GP-MF6J

Vulnerability from github – Published: 2026-09-22 20:34 – Updated: 2026-09-22 20:34
VLAI
Summary
Unleash: CR-approval email renders user-controlled raw HTML
Details

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:

{{{ 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:
</a><a href="https://example.com">Approve change request</a>
  1. Create a change request that requires approval.
  2. 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.

Severity
2.1 (Low)
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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "unleash-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-76909"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-22T20:34:38Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "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\u0027t 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\u0027s 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\u003c/a\u003e\u003ca href=\"https://example.com\"\u003eApprove change request\u003c/a\u003e\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.",
  "id": "GHSA-7hvx-28gp-mf6j",
  "modified": "2026-09-22T20:34:38Z",
  "published": "2026-09-22T20:34:38Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Unleash: CR-approval email renders user-controlled raw HTML"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.