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Should you update to Firefox 157.0.1?

From Firefox updates, in the HARD wiki · Updated
This article is about one Firefox release. For the latest version, see Firefox updates.

No: install Firefox 159.0.1 instead. Firefox 157.0.1 is a security update Mozilla released on 6 Oct 2026 for Mac, Windows and Linux. It fixes 1 security flaw, 0 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It has since been replaced by Firefox 158, released 13 Oct 2026, which includes all of its fixes.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 157.0.1, so there’s no reason to stop at this one. Software Update offers the newest version your device can run.

Is Firefox 157.0.1 still safe?

Not any more. The 4 updates since, up to Firefox 159.0.1, fix 249 security flaws that Firefox 157.0.1 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 1 security flaw, 0 rated critical and 0 high by Mozilla.[1] None is rated critical or high.

How to update, and how long it takes

A minute or two. Firefox restarts and reopens your tabs.

  1. Open Firefox’s About window.Open the ☰ menu → Help → About Firefox. Firefox checks for the update and downloads it.
  2. Click Restart to update Firefox.Firefox reopens your windows and tabs. Until it restarts, the old, unfixed version keeps running.
  3. 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 158 or later.

157 vs 157.0.1

Firefox 157, released 29 Sep 2026, fixed 76 security flaws. Firefox 157.0.1 fixes 1 security flaw and includes the fixes before it, so going straight to 157.0.1 gets you both.

References

  1. ^ Mozilla. “Security Vulnerabilities fixed in Firefox 157.0.1”, 6 Oct 2026.