Researchers found a flaw in Opera GX, the gaming-focused version of the Opera browser, that let a malicious website silently install a browser add-on and use it to lift specific data from the pages a victim visits. In a proof of concept, they reconstructed a signed-in user's full Gmail address from a single visit, with no click. Opera has patched the flaw and says it found no evidence that it was ever used in the wild. The fix shipped in Opera GX version 130.0.5847.89, so anyone on a current build is already covered; you can confirm yours at opera://about. There is no CVE. Because the attack needed no clicks or approvals, there was no workaround short of the patch. Opera's bug bounty team rated the issue P1, its top severity, and paid the maximum $5,000 award for a critical bug. How the attack works GX Mods let you reskin Opera GX with custom sounds, themes, wallpapers, and CSS that restyles the sites you visit. They ship as .crx files, like browser extensions, but they cannot run JavaScript and hold no permissions. The weakness is in how they install: Opera's mod pipeline downloads and enables a mod automatically, with no approval prompt. So a malicious page can install one silently, for instance by loading a hidden iframe pointed at a .crx file. The only sign is a notification bar below the address bar telling you a mod was added, with a Remove button. This auto-install behavior is not new. The researcher Renwa identified it back in 2023 and, by escalating an installed mod into a full extension, used it to spoof the browser's address bar. Opera patched that specific attack in March 2023 but left the underlying auto-install in place, which is what this new research builds on. A silent look-and-feel