CVE-2026-71502 Unauthenticated Stored Vue Template Injection Leads to Cross-Site Scripting in CTI-Transmute
Unauthenticated attackers can inject malicious Vue templates to execute arbitrary JavaScript, potentially stealing data or hijacking sessions in CTI-Transmute.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-71502?
CVE-2026-71502 is a medium-severity cross-site scripting vulnerability in misp cti-transmute, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
CTI-Transmute contains a stored cross-site scripting vulnerability caused by insufficient neutralization of Vue template expression delimiters in server-rendered user-controlled data.
An unauthenticated attacker can create a public conversion whose name or description contains a malicious Vue expression using the application's configured [[ ... ]] delimiters. User profile names may provide an additional injection vector. Although Jinja HTML escaping is applied, the resulting value is subsequently included in a DOM region compiled by Vue.
Vue interprets the attacker-controlled value as a template expression rather than ordinary text. By accessing the JavaScript Function constructor from within the expression, an attacker can execute arbitrary JavaScript in the security context of the CTI-Transmute origin. The application's nonce-based Content Security Policy does not prevent exploitation because the Vue runtime compiler requires the unsafe-eval policy exception.
The malicious payload is stored by the application and executed whenever another user opens an affected page, such as the public conversion detail page. The victim may be a normal user or an administrator. Successful exploitation could allow the attacker to:
* Access data available to the victim through the application. * Extract API keys, tokens, or other sensitive information exposed to the page. * Perform authenticated actions using the victim's session. * Modify conversions or other application data. * Escalate the impact by targeting an administrator.
A demonstrated payload can use [].constructor.constructor(...) to obtain the JavaScript Function constructor and execute arbitrary code. The regression tests also show that a short first-stage payload could retrieve an uncapped conversion description and evaluate a larger second-stage payload.
The patch addresses the vulnerability by registering a global Jinja finalize hook that inserts a zero-width Unicode word joiner inside every Vue delimiter found in server-rendered values. This prevents Vue from recognizing the values as template expressions while preserving their visible representation.
Which versions are affected by CVE-2026-71502?
How do I fix CVE-2026-71502?
No fix has been published for CVE-2026-71502 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-71502 being exploited?
There is no known exploitation of CVE-2026-71502 in the wild and no public exploit code.
Sources
Also known as GHSA-6x7q-w685-49vg.