GHSA-7hvx-28gp-mf6j: XSS
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/unleash-serverto a version that resolves this vulnerability.Fixed in 8.0.3
Event History
Frequently Asked Questions
Who can exploit this issue?
A project member who can create change requests can inject HTML through a change-request title or display name. Exploitation also requires change-request approval notification emails to be enabled and a change request that requires approval.
Which deployments are known to be exposed?
The issue was demonstrated on an Enterprise deployment with change requests and approval emails enabled. The available information does not confirm whether the Enterprise platform uses vulnerable code or sanitizes these inputs.
What is the practical impact of successful exploitation?
Attacker-controlled HTML is rendered in approval notification emails. This can alter the email content, such as replacing or adding an approval link that directs recipients to an attacker-controlled destination.
How can I check whether we are affected?
Review whether the requested change-request approval email template renders changeRequestTitle, requesterName, requesterEmail, or changeRequestLink with unescaped Mustache triple-stash syntax, and whether sendRequestedCRApprovalEmail renders that template. In a non-production test, create an approval-required change request using HTML in an allowed title or display-name field and inspect the resulting email.