cve-2026-11645cve-2026-45657patch-tuesdaychromezero-day

June 2026 Patch Tuesday: An Actively-Exploited Chrome Zero-Day and a Wormable Windows RCE

Two June 2026 bugs change when you patch, not just whether: CVE-2026-11645 (Chrome V8, actively exploited) and CVE-2026-45657 (wormable Windows Kernel RCE, C...

Diego Diaz
2 min

Every month brings a Patch Tuesday, and most of them blur together. This one shouldn't. Two of the June 2026 fixes change the math on when you patch, not just whether you do.

The two that matter

CVE-2026-11645 is an out-of-bounds read and write in V8, the JavaScript and WebAssembly engine inside Google Chrome (CVSS 8.8). The detail that matters: it is already being exploited in the wild. Google shipped the fix on June 9. If your team or your users browse the web in Chrome — or any Chromium-based browser — this is a "today" problem, not a "this sprint" problem.

CVE-2026-45657 is a remote code execution flaw in the Windows Kernel, rated CVSS 9.8. It is unauthenticated and wormable: an attacker can run code at SYSTEM level with no user interaction, and a bug like that is the raw material for self-propagating malware. There is no confirmed exploitation yet — which is exactly the window you want to patch in.

What "actively exploited" actually changes

A normal CVSS-8 bug gives you a runway: triage, schedule, test, deploy over a couple of weeks. "Actively exploited" deletes that runway. It means a working exploit already exists, attackers are already using it, and every hour you wait is an hour you are knowingly exposed to a known technique. For CVE-2026-11645, the only correct patch timeline is "now."

The wormable kernel bug is the inverse risk: nobody is using it yet, but the moment a reliable exploit goes public, mass scanning starts within hours. The early-stage teams that get hit are the ones who told themselves "we'll get to it after the launch."

The patch-now checklist

  • Chrome / Chromium everywhere. Force-update Chrome on every machine, plus Edge, Brave, and anything Electron-based that bundles Chromium. Verify the version — don't assume auto-update ran.
  • Windows hosts, servers first. Apply the June cumulative update to internet-facing Windows servers before workstations. A wormable, unauthenticated kernel RCE is worst where it is reachable.
  • Inventory what you actually run. You can't patch the Chromium you forgot ships inside your desktop app or your CI runners.
  • Confirm, don't trust. "Patch deployed" and "patch applied and rebooted" are different states. Kernel patches usually need the reboot.

Where this fits

Patching your stack is step zero — the part you get no credit for until you skip it. What it does not cover is the code you shipped: the wildcard CORS, the secret in the repo, the auth check that isn't quite a check. That is the layer Sable scans for. But none of it matters if the box underneath is running a kernel an attacker can own for free. Patch first, then go find what your own app is leaking.