What it is
XSS is a web bug where attackers make a site run their script in your browser. That script can read what you see, steal session cookies, change forms, or redirect you to fake pages. It shows up in a few flavors (reflected, stored, DOM-based), but the idea is the same: untrusted input becomes active code. More info: https://gridinsoft.com/xss
Why it matters
If a script runs in your session, it can act as you - grab logins, send messages, or change account settings without your click.
How it works - quick tour
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Inject: attacker slips script into a link, comment, profile, or search box.
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Render: the site doesn’t sanitize it and sends it to browsers.
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Execute: your browser runs the code as if it came from the site.
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Abuse: the script steals cookies/tokens, rewrites the page, or sends data out.
Red flags
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A link with odd parameters like
<script>,onerror=, or data that looks like code. -
Pages that suddenly auto-fill or show pop-ups that don’t match the site’s style.
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You click a site link and get instantly redirected through strange domains.
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Your password manager won’t autofill on a page that looks normal.
Do it right
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Don’t click weird tracking-looking links from DMs or comments; open the site from your bookmarks.
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Log out and back in if a page looks tampered; clear site data for that domain.
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Turn on a password manager and MFA - they limit damage if a session is stolen.
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Keep your browser and extensions updated; remove extensions you don’t need.
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If you run a site: validate/escape user input and use Content Security Policy (CSP).