Should you update to Thunderbird 152.0.1?
No: install Thunderbird 159 instead. Thunderbird 152.0.1 is a security update Mozilla released on 30 Jun 2026 for Mac, Windows and Linux. It fixes 2 security flaws, 0 rated critical and 1 high by Mozilla.[1] None of them is known to be used in attacks.
It has since been replaced by Thunderbird 153, released 21 Jul 2026, which includes all of its fixes.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 Thunderbird 159 instead. Thunderbird 159 came out on 27 Oct 2026 and includes every fix in Thunderbird 152.0.1, so there’s no reason to stop at this one. Software Update offers the newest version your device can run.
Is Thunderbird 152.0.1 still safe?
Not any more. The 8 updates since, up to Thunderbird 159, fix 558 security flaws that Thunderbird 152.0.1 doesn’t, and each became public the day its fix shipped. Installing it is safe: get it only from Thunderbird’s own About window, or thunderbird.net, never from a link in an email, text or pop-up.
What it fixes
Mozilla lists 2 security flaws, 0 rated critical and 1 high by Mozilla.[1] The critical or high one is:
| Flaw | Severity | What Mozilla calls it |
|---|---|---|
CVE-2026-57963 | High | Chat UI manipulation by injection |
How to update, and how long it takes
A minute or two. Thunderbird restarts and your mail stays where it was.
- Open Thunderbird.On a Mac choose Thunderbird → About Thunderbird; on Windows open the ☰ menu → Help → About Thunderbird.
- Let it download the update.The About window checks for one by itself; when it says “Restart to update Thunderbird”, click it.
To check it worked: The same About Thunderbird window shows the version under the name. It should say 153 or later.
152 vs 152.0.1
Thunderbird 152, released 16 Jun 2026, fixed 40 security flaws. Thunderbird 152.0.1 fixes 2 security flaws and includes the fixes before it, so going straight to 152.0.1 gets you both.
- Before: Thunderbird 152, 16 Jun 2026, 40 security flaws
- After: Thunderbird 153, 21 Jul 2026, 61 security flaws
- Thunderbird updates, every release and the latest version
- Updates, the latest version of everything HARD tracks
References
- ^ Mozilla. “Mozilla Foundation Security Advisory MFSA 2026-63”, 30 Jun 2026.