Should you update to Firefox 152.0.6?
No: install Firefox 159.0.1 instead. Firefox 152.0.6 is a security update Mozilla released on 14 Jul 2026 for Mac, Windows and Linux. It fixes 2 security flaws, 2 rated critical and 0 high by Mozilla.[1] None of them is known to be used in attacks.
It has since been replaced by Firefox 153, released 21 Jul 2026, which includes all of its fixes. If you’re on an older version, install that instead.
Should you update?
No: install Firefox 159.0.1 instead. Firefox 159.0.1 came out on 3 Nov 2026 and includes every fix in Firefox 152.0.6, so there’s no reason to stop at this one. Software Update offers the newest version your device can run.
Is Firefox 152.0.6 still safe?
Not any more. The 10 updates since, up to Firefox 159.0.1, fix 548 security flaws that Firefox 152.0.6 doesn’t, and each became public the day its fix shipped. Installing it is safe: get it only from Firefox’s own About window (☰ menu → Help → About Firefox), never from a link in an email, text or pop-up.
What it fixes
Mozilla lists 2 security flaws, 2 rated critical and 0 high by Mozilla.[1] The 2 critical and high ones are:
| Flaw | Severity | What Mozilla calls it |
|---|---|---|
CVE-2026-15718 | Critical | Invalid pointer in the JavaScript: WebAssembly component |
CVE-2026-15719 | Critical | Site isolation in the DOM: Navigation component |
How to update, and how long it takes
A minute or two. Firefox restarts and reopens your tabs.
- Open Firefox’s About window.Open the ☰ menu → Help → About Firefox. Firefox checks for the update and downloads it.
- Click Restart to update Firefox.Firefox reopens your windows and tabs. Until it restarts, the old, unfixed version keeps running.
- Leave automatic updates on.In Settings → General → Firefox Updates, keep “Automatically install updates” selected.
To check it worked: The ☰ menu → Help → About Firefox shows the version. It should say 153 or later.
152.0.4 vs 152.0.6
Firefox 152.0.4, released 30 Jun 2026, fixed 1 security flaw. Firefox 152.0.6 fixes 2 security flaws and includes the fixes before it, so going straight to 152.0.6 gets you both.
- Before: Firefox 152.0.4, 30 Jun 2026, 1 security flaw
- After: Firefox 153, 21 Jul 2026, 63 security flaws
- Firefox updates, every release and the latest version
- Updates, the latest version of everything HARD tracks
References
- ^ Mozilla. “Security Vulnerabilities fixed in Firefox 152.0.6”, 14 Jul 2026.