Frontend-Security

Budibase makes it easy to ship internal tools fast. That speed is great for product teams and terrible for security if nobody stops to ask a basic question: where does this data come from, and how is it rendered? That question matters because XSS in Budibase apps usually does not come from some dramatic “hacker-only” feature. It comes from normal app-building behavior: user-generated content, dynamic bindings, custom components, markdown-ish fields, embedded HTML, and API data that gets trusted too early. ...

Cross-site scripting is still one of the easiest ways to turn a small rendering mistake into a full account takeover. If you build donation flows, event pages, admin dashboards, checkout forms, or email template editors like the kinds of features you’d expect around Humanitix, you’re handling user-controlled content constantly. That’s exactly where XSS shows up. The boring version of XSS advice is “escape output.” True, but too shallow to be useful. Real apps have rich text, markdown, embedded widgets, analytics snippets, query-string state, and legacy code that still pokes the DOM directly. That’s where teams get burned. ...

I’ve worked on enough legacy jQuery codebases to know how XSS sneaks in: not through one giant mistake, but through dozens of “harmless” shortcuts. A team I helped had a customer support dashboard built over several years. Classic jQuery app. Server-rendered shell, lots of AJAX fragments, user comments, admin notes, profile fields, search terms reflected back into the UI. Everything felt normal until a security review found stored and reflected XSS in multiple places. ...

ToolJet is great for shipping internal tools fast. That speed is also exactly why people end up shipping XSS bugs fast. I’ve seen the same pattern over and over: a team treats ToolJet like a safe abstraction layer, assumes the platform handles all rendering risks, then mixes user input into HTML, JavaScript, or query results. Now the “internal tool” is running arbitrary script in an admin’s browser. That’s still XSS. Internal apps still hold production data, admin sessions, API tokens, and enough privileges to ruin your week. ...

Carrd is deceptively simple. That’s why people get sloppy with it. You drag in text, forms, embeds, maybe a custom code block, publish, and move on. From an XSS perspective, that “simple landing page builder” can still become a script execution surface if you treat every HTML box, embed, and third-party widget like a safe sandbox. It isn’t. This guide is the practical version: where XSS shows up in Carrd, what Carrd does and doesn’t protect you from, and what to actually paste into your setup. ...

Cal.com embeds are convenient, but they also create one of my least favorite frontend security situations: third-party UI mixed with app code that was never designed for hostile input. The Cal.com script itself isn’t the usual problem. The problem is everything around it: how teams build embed URLs, how they pass prefill data, how they read query params, and how they inject user-controlled values into the page next to the widget. ...

Shopify developers often assume Liquid gives them automatic XSS protection. That assumption is where trouble starts. Liquid does help, but only in very specific contexts. The moment you move data from HTML text into attributes, JavaScript, JSON, URLs, or raw HTML blocks, the safety story changes fast. I’ve seen plenty of themes that look clean at first glance and still leave enough room for script injection through product data, metafields, cart attributes, or section settings. ...

Qwik does a lot right for security by default, but “by default” is where people get lazy. I’ve seen teams assume that because they’re using a modern framework, XSS is basically handled. Then somebody adds raw HTML rendering for a CMS snippet, builds a cute dynamic link component, or injects JSON into the page during SSR, and now the app has a very old-school bug wearing a very modern outfit. ...

v-html is one of those Vue features that feels convenient right up until it becomes a security incident. If you render untrusted HTML with v-html, you are bypassing Vue’s normal escaping protections and handing the browser raw markup. That means any unsafe HTML that survives into that string can execute script, steal session data, or manipulate the page in ways you did not expect. For a developer audience, the rule is simple: ...

DOM clobbering is one of those bugs frontend teams accidentally create while thinking they are dealing with “just HTML”. Then it turns into script execution, broken security assumptions, or both. The short version: browsers expose some elements with id or name values as properties on global objects like window and sometimes on forms. If your JavaScript trusts those properties, an attacker can inject markup that overwrites what your code thinks is a safe variable, config object, or URL. That often becomes XSS. ...