Thunderbird 52.6.0 with security fixes released

Thunderbird 52.6.0 is a security update for the popular desktop email client. The release is available via the email client's automatic update feature and also on the official project website.
Thunderbird users can run a manual check for updates with a click on Help > About Thunderbird. If the menu bar is missing, tap on the Alt-key to display it.
Thunderbird will pick up the new update and download and install it automatically.
Thunderbird 52.6.0
Thunderbird 52.6.0 is a security and maintenance release.
The team lists all fixed security vulnerabilities on this page. The bulk of issues cannot be exploited through emails because scripts are disabled by default when reading emails. They may be exploited however in browser or browser-like contexts.
- CVE-2018-5095: Integer overflow in Skia library during edge builder allocation
- CVE-2018-5096: Use-after-free while editing form elements
- CVE-2018-5097: Use-after-free when source document is manipulated during XSLT
- CVE-2018-5098: Use-after-free while manipulating form input elements
- CVE-2018-5099: Use-after-free with widget listener
- CVE-2018-5102: Use-after-free in HTML media elements
- CVE-2018-5103: Use-after-free during mouse event handling
- CVE-2018-5104: Use-after-free during font face manipulation
- CVE-2018-5117: URL spoofing with right-to-left text aligned left-to-right
- CVE-2018-5089: Memory safety bugs fixed in Firefox 58, Firefox ESR 52.6, and Thunderbird 52.6
Thunderbird 52.6.0 fixes three usability issues as well.
- Searching message bodies of messages in local folders, including filter and quick filter operations, not working reliably: Content not found in base64-encode message parts, non-ASCII text not found and false positives found.
- Defective messages (without at least one expected header) not shown in IMAP folders but shown on mobile devices
- Calendar: Unintended task deletion if numlock is enabled
The search issue fix is probably the biggest improvement in the release. Thunderbird's built-in search did not work reliably in some cases. If you noticed in the past that mails were not returned by the search even though they should, this may have been the reason for that.
Thunderbird did not display defective messages in IMAP folders under certain circumstances. This is fixed as well and should work as intended.
Last but not least, a bug caused tasks to be deleted in the built-in calendar if Numlock was activated.
Closing Words
Thunderbird 52.6.0 is a security update and as such should be installed asap. I did not notice any issues yet after the upgrade but that is just with a couple of minutes of using the new version. If anything comes up I'll update the article.
Now You: Which email client or service do you use?
Related articles
- How to encrypt your emails in Thunderbird
- ProtonMail Bridge: encrypted email for Outlook, Thunderbird, and other email clients
- Thunderbird Audit reveals unpatched security issues
- Thunderbird Photon Design refresh and WebExtensions
- Thunderbird's new home is.. The Mozilla Foundation


You said that Outlook isn’t your main email client, so which is your main one?
I think its thunderbird
It is Mozilla Thunderbird.
Awesome! This actually solved my problem… what a stupid bug.
If this is the same bug that I’ve encountered, there may be another fix: (1) hover over open Outlook item in Taskbar, cursor up to hover over Outlook window item, and right-click; (2) this should give you Restore / Move / Size / Minimize / Maximize — choose Move or Size; (3) use your cursor keys, going arbitrarily N/S/E/W, to try to move or size the Outlook window back into view. Basically, the app behaves as though it were open in a 0x0 window, or at a location that’s offscreen, and this will frequently work to resize and/or move the window. Don’t forget to close while resized/moved, so that Outlook remembers the size/position for next time.
THANK YOU Claude!!! I could get the main window to launch but could not get any other message window to show on the desktop. You are my hero!!!!
Solved my issue! 6 years later and this is still problem…
Fantastic. Thank you. Size did the trick.
This solved my Outlook problem, too. Thank you. :)
Thank you so much, this started happening to me today and was causing big problems. You are a life saver, I hope I can help you in some way some day.
You are a god – thank you!
thanks a lot…. work like charm.. :-)
Yah…thanks Claude. I’ve been having the same problem and tried all the suggestions…your solution was the answer. It had resized itself to a 0/0 box. Cheers
Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
Thank you
Thanks a lot for the article. Don’t know why it happenend, don’t know how it got fixed, but it was really annoying and now it works :-)
Thanks a lot. I was facing this issue from past 3 week. I tried everything but no resolution. The issue was happening intermittently and mainly when I was changing the display of screen ( as i use 2 monitors). The only option i had was to do system restore. But thanks to you.
I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!
Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007
Great tip! Thanks!
Worked for me, too – thank you!!!
It’s Worked for me, too
thank you very much!
I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!
Thank you so much. Solved!
Considering you published this in 2012, incredible not been debugged by Microsoft.
Thank you again. M
This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.
Thanks.
Great tip. Thank you!!!! If it helps, I had to use the Control Key and the arrow keys at the same time to bring my window back into view. Worked like a charm.
Thank you, this worked !!!!
Man, you are a fucking god. Thanks a lot, what an annoying bug!!
Awesome, this post solved the issue. Many thanks!