Recently, I have experienced an erroneous browser launch, simply by
clicking on the title of the message in the list pane. This problem
seems to occur when clicking on emails from Tesco <http://tesco.com>.
The web page opened has a long and complicated URL, but the page
contains only a single pixel which shows up as a white dot on a black
background.
Obviously, it is likely that there is something strange about that
source, but the problem doesn't occur if I click on the same email in a
different email client (in this case Evolution). I am running
Thunderbird 140.5.0esr (64-bit) on Kubuntu Linux 24.04
I have tried various Settings as advised by web searches and also the
solutions suggested in Thunderbird Help (Troubleshooting Mode and
Troubleshooting Information). I then posted the above to Mozilla
Support and eventually got the following:
No one wants to have a go here. I don't want to either really. But
what you are seeing is what is talled a web bug. It is a single
pixel image used by commercial mailers to track your activities in
the email when and where is is read being the most ovvious but also
how many times you open it as it is fetched everytime you look at
the email.
Why it is opening in your browser can at this point only be
conjecture. But I am guessing it may be like the old twitter icons
and been included in the message as a remote image, but the link is
to a script that serves the image, not to the image. Thunderbird
does not accept output from scripts so the browser open to get the
image. You might want to consider blocking remote images.
A script can grab a whole lot more fingerprinting information that
simply serving an image so there are privacy implications for these
things
I responded to this pointing out that the problem has only occurred in
Thunderbird and also only in recent weeks, but I have not received any
response to date. (I even opened an old message which did not exhibit
this problem, but does now.)
I also asked why 'No one wants to have a go here. I don't want to either
really'. Again no response.
Obviously, I could switch to Evolution, but it does not support
importing settings from Thunderbird, so I would have to laboriously
enter all of the aliases (Identities) that I have created over the last
20 years or so. I could instead block images as suggested by the
response, but that is quite a serious limitation of functionality just
to overcome something that appears to be handled by other browsers. Can
anyone shed light on any other way to get round this?
--
Terry Coles
--
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