Susceptible to security exploits; a crash in the plugin crashed the entire browser.
You're looking for information about plugins, specifically Shockwave Flash. Here's what I found: about plugins shockwave flash
In the late 1990s, the World Wide Web was a largely static environment. Websites were built with basic HTML—text, images, and blue hyperlinks. Susceptible to security exploits; a crash in the
Now, when you visit an old .swf file, you’re met with a gravestone: Susceptible to security exploits
Malicious websites exploited unpatched plugins to install malware without user consent.