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ZDNET's key takeaways

• Big changes for Google Chrome have been in the pipeline since 2019.
• These changes have a significant impact on the capabilities of ad blocker extensions.
• Adblockers have implemented workarounds, but these make them less effective at blocking ads.

The end is nigh for advanced ad blockers in Google Chrome. Under-the-hood changes in the browser will have a significant impact on security and the level of control end users have over the web content displayed to them. Google says one of those changes -- related to the mechanism that controls which powers extensions have over web pages loaded into the browser -- will improve privacy, security, and performance.

Also: Half of all cyberattacks start in your browser: 10 essential tips for staying safe

Google, which generates over 70% of its revenue from advertising (over $260 billion in 2025), is making changes to the Manifest API system, a part of the browser that controls how extensions interact with the web page being loaded. The current system, Manifest V2, is being replaced by Manifest V3, and this update limits the number of filtering rules that an extension can apply and completely removes the ability to dynamically block content. 

Among the biggest casualties of this change are ad-block extensions such as uBlock Origin and AdBlock. 

The transition from Manifest V2 to V3 is expected to be completed when Chrome version 150 is released (rumored to land on June 30). After that, updating to the latest release will kill all extensions that rely on Manifest V2. 

Because of the power and versatility offered by Manifest V2, extensions like uBlock Origin had become more like mini firewalls running within the browser, capable of running really complex anti-tracking and anti-circumvention techniques and intercepting and modifying every web request in real-time. 

Also: The best ad blockers: Clean up your browsing experience

The shift to Manifest V3 dumbs these extensions down, turning them into little more than a list of filtering rules. The testing I've done suggests that while Manifest V3-capable ad-block extensions still block the majority of ads, I am seeing more ads fall through the cracks than I usually would. 

To put it in numbers, Manifest V3 caps extensions to 30,000 filtering rules, while an ad blocker might use anywhere from 80,000 to 300,000 rules. 

There are adblockers that have been designed to work under Manifest V3 (such as uBlock Origin Lite, AdGuard, and Ghostery), but they lack a lot of the more advanced features. 

And as soon as Manifest V3 is fully released, I expect advertisers to make greater use of anti-circumvention techniques.

On the whole, I don't have a problem with web ads. Yes, they can be annoying -- and some sites can certainly be a hell stew of pop-ups and ads -- but I see them as a way to pay content creators. My problem with the switch from Manifest V2 to V3 is that it takes control away from the end user, a move that will make us less safe. Sure, there were examples of Manifest V2 being abused by scammers, such as when the "Save Image as Type" extension was hijacked by hackers in 2025 and modified to steal affiliate commissions. 

Also: Why your RAM options cost 4X more now than last year - even legacy tech prices aren't immune

But Manifest V2 also had the power to do good. A lot of good. 

Take the epidemic of ClickFix malware that's popping up on thousands of hacked websites. These compromised sites display a fake Cloudflare or CAPTCHA verification dialog that tries to get visitors to copy‑paste a command, inadvertently infecting their systems with malware. One of the best ways to protect against a threat like this is to use an extension like NoScript. 

The shift to Manifest V3 will drastically reduce the effectiveness of tools like NoScript. 

I'm not alone in worrying about the effect Manifest V3 will have. The Electronic Frontier Foundation (EFF) has been critical of the change since 2019. Bottom line: the EFF believes the changes won't stop malicious extensions but will hurt innovation, reduce extension capabilities, and harm real-world performance. 

Think you can just hand over the job of ad and JavaScript blocking to something like Pi-Hole or an AdBlocker running on a Pi or an ESP32? While these tools can block ads and other web components, such as scripts, you can only use them to block web addresses at the DNS level (a process called DNS sinkholing). This is because most web traffic is encrypted and can't be inspected before it gets to the browser, so that was the only place where advanced filtering could be done.

Also: 6 top free secure DNS services I trust - and why I always encrypt my web browsing

But not anymore.

The same goes for DNS solutions, such as AdGuard DNS, NextDNS, or Cloudflare Access.

Not using Google Chrome? Here's how things stand for you right now. Firefox has pledged to continue to support Manifest V2 extensions, and Brave has put in place workarounds to maintain support for AdGuard, uBlock Origin, uMatrix, and NoScript by hosting them on the backend. 

As for Microsoft Edge, that browser is currently phasing out Manifest V2 support in favor of Manifest V3.