How to Remove Sensitive HTML Comments

An HTML comment (<!-- like this -->) never renders on screen, but it is not hidden from anything that reads the response body instead of the rendered page. "View Source" in any browser shows it, curl shows it, and so does every crawler that fetches your HTML directly. The sensitive_html_comment check scans your page's raw source for comment blocks and flags the ones that look like they carry internal or sensitive detail rather than harmless markup notes.

What typically trips this check: filesystem paths (Unix-style paths like /var/www/html/ or /home/deploy/, or a Windows path under inetpub), private IP ranges (10.x.x.x, 172.16-31.x.x, 192.168.x.x), developer shorthand (TODO, FIXME, HACK, "remove before launch", "don't tell client"), credential-shaped strings (password, api_key, secret, token), CMS or plugin/theme version banners, and mentions of staging, dev, or internal hostnames.

Not every comment is a problem. <!-- start hero section --> or <!-- Google Tag Manager --> are structural markers and get left alone; they carry no information an attacker or competitor could use. The finding is specifically about comments that leak something internal, and it's a warning rather than a critical error because reading a comment isn't itself an exploit. No code executes and no data is stolen just because the text is present.

Worth being upfront about: this check is pattern-based, so it will occasionally flag something borderline, a TODO about page copy rather than code, or a version string that's already public elsewhere. Treat a flag as a prompt to review the comment, not an automatic verdict that your site is compromised.

Information disclosure is a reconnaissance tool, not an exploit by itself, but it shortens the distance to one. A comment that names an exact CMS, plugin, or theme version tells an attacker precisely which known vulnerabilities to try, skipping the guesswork of fingerprinting your stack first. Internal IPs and file paths reveal your server layout and OS, which narrows what they need to probe. Penetration testers flag this category of finding constantly for exactly this reason: none of it is a breach, all of it makes a real breach easier if another weakness exists.

Occasionally a comment holds more than a note, an actual API key or password pasted in during debugging and forgotten. If that's what triggered this flag, treat it as more urgent than general hygiene: rotate the credential immediately, then remove the comment. A leaked secret doesn't become safe just because it's easy to fix in hindsight.

The angle specific to AI crawlers is worth understanding on its own terms. Bots like GPTBot, ClaudeBot, PerplexityBot, and CCBot fetch the raw HTML response the same way curl does; they don't render the page in a browser that visually discards comments the way a human reader's eyes skip past invisible markup. Whatever sits in a comment is exactly what these systems receive, and it can persist in whatever index, cache, or training pipeline consumes that fetch. Invisible on the page and invisible to machines are not the same thing, and comments are a common place people forget that.

To be clear about what this isn't: Google does not rank pages down for having HTML comments, and this finding has no direct SEO effect. The value of fixing it is entirely security hygiene, reducing what a stranger can learn about your stack for free, not search visibility.