What potential issues can arise when using iframes to embed external content, such as forums or wikis, in PHP websites?

Potential issues that can arise when using iframes to embed external content in PHP websites include security vulnerabilities such as clickjacking, where an attacker can trick users into clicking on malicious content disguised as legitimate content. To prevent clickjacking attacks, it is recommended to set the X-Frame-Options header to deny or sameorigin in the HTTP response headers of the embedded content. 

header("X-Frame-Options: DENY");

Keywords

iframes embedding external content security vulnerabilities cross-site scripting

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