Researchers: hackers have used an 18-year-old flaw in how Safari, Chrome, and Firefox on macOS handle queries to a 0.0.0.0 IP address to breach private networks
Weaknesses in Chrome, Firefox and Safari gave hackers a route into internal networks, even those protected by firewalls, security researchers warn.
Context & Ripple Effects
This report adds a network-boundary dimension to recurring macOS browser security issues. Earlier coverage included WebKit flaws used in malicious-ad redirection and a WebKit-based attack that could expose secrets from a visited site.
The distinction here is that browser requests can become a path toward resources assumed to be protected by a private-network firewall. That makes browser network-request behavior, not just page content or credential handling, part of the local security perimeter.
First-order effects
- macOS users who visit a malicious site may expose reachable private-network services through Safari, Chrome, or Firefox behavior around 0.0.0.0 requests.
- Organizations relying on firewalls as the principal boundary for internal web services must treat browser-originated access as a reported exposure path.
Second-order effects
- Browser vendors face pressure to align their handling of special local-address requests, since inconsistent protections leave users exposed through the least restrictive browser.
- Security teams may need to reassess internal services that are reachable from employee devices, rather than assuming a browser cannot bridge public web content and private-network endpoints.
Third-order effects
- If similar cases persist, browser security will increasingly be judged on how reliably it separates public-web origins from local and private-network resources across platforms.
- The episode reinforces a broader shift from perimeter-only defenses toward layered controls on browser access, local services, and network-origin validation.
The trend: Browsers are becoming a more consequential enforcement layer between untrusted web content and private computing environments.