Chrome reverts a debugger policy that broke enterprise extensions

Google has rolled back an enterprise policy change in Chrome 155 that broke the chrome.debugger API on managed browsers. The fix shipped as a server-side configuration update on 3 November, so most affected browsers correct themselves without an upgrade.

Chrome 155, stable since 6 October, tied debugger access to an all-or-nothing check. If a managed browser’s ExtensionSettings policy configured even one host in runtime_blocked_hosts, or restricted screenshots through a DLP rule, chrome.debugger.attach() failed everywhere, not just on the restricted site, with the error “Host access is restricted by policy.” Unmanaged browsers and personal profiles were never affected. Admins who haven’t received the automatic rollback yet can force the old behaviour immediately:

chrome --disable-features=ExtensionDebuggerStrictPolicyRestrictions

Why it matters: if an extension using the debugger permission started failing for your enterprise users last month, this is why, not a bug in your code. Google’s own guidance now tells extension developers to handle attach rejections explicitly and, where possible, move off raw Chrome DevTools Protocol access to chrome.scripting or chrome.declarativeNetRequest instead.