Spammy 404s: Should I Worry?

[FSCInteractiveLLC]

One of my sites is getting a ton of spammy 404s with porno-like URLs. All of these 404s are linked from other sites that I assume also got hacked, and when I click on them, they are also 404s.

So I'm assuming some spam site is tricking the Googlebot into thinking these URLs exist. But is this going to affect my site & SEO directly?

Is it worth disavowing all of the sites linking to me? Is Google even considering these real links? Did these pages ever actually exist anywhere?

Don't have a hacker-brain whatsoever so I need some enlightening.

I've been told I shouldn't worry but it seems like something I should worry about...Any help is greatly appreciated

(I've updated to the newest Wordpress and Sucuri).

[FSCInteractiveLLC]

The pages definitely don't exist anywhere.

Does this mean I have nothing to worry about?

[BradsDeals]

There is a link spam technique out there that is used to hide actual links from the site owners. So, if you are logged into your WordPress site, for example, the links and pages won't appear to be there. But, if you are logged out then the pages will be there, visible to the search engines and the public.

Often those injected spam URLs are hidden using javascript. There's a Chrome plugin called Quick Javascript Switcher that will let you toggle JS on and off. Once it's off, if there are injected URLs on your site, you should be able to see them.

[GlobeRunner]

The first thing I recommend is to make sure that those are actually 404 errors on your site that the search engines (and regular users) can see. There is a link spam technique out there that is used to hide actual links from the site owners. So, if you are logged into your WordPress site, for example, the links and pages won't appear to be there. But, if you are logged out then the pages will be there, visible to the search engines and the public.

I would look in Google to see if those 404 pages on your site are indexed. Try a site:yourdomain.com search to see if they're indexed. Then, use a crawler to crawl your own website to see if the crawler can find those 404 pages.

Typically, when you see those errors, the site has been hacked and now they've been removed. Or, those pages are on your site but when you go to them they appear to be 404s. I recommend you investigate this further to make sure that the pages or the errors do not exist.

[RobertFisher]

As to should you worry, we need more info. Of all the links you show in a tool like ahrefs or Majestic, what percentage are these links?

Can you pm me a sample of one or two of them? I will be happy to tell you what I think once I am clear on what they are. We also do a ton with WP so could probably give you some direction there. I am only saying PM so that you can disclose if you don't want to disclose in public. I am not going to in any way try to sell you on our services and if you wanted service I would refer you as I don't like people hawking through Moz Q&A. 
Best

[PatrickDelehanty]

Hi there

Has this been an ongoing issue and you are seeing more and more 404 links coming in? If so, Google has ways of notifying them on potentially spammy / hacked websites, so you could start there.

If it's something where these links are taking up a good portion of your backlink profile, I would do a quick audit and possibly disavow. This may take a bit of work, so if you're not comfortable, Moz has a great recommended companies list of agencies / consultants that will be more than happy to help.

Let me know if this helps or if you have any more questions! Good luck!
Patrick