Created attachment 1103965 [details]
small text fragment that exhibits the problem

Description of problem:
I tried to send a mail and evolution hung before sending, allocating memory like crazy (observed in top and strace). If I didn't interrupt it in time (2 or 3 times out of many attempts), it ate up so much memory eventually that X11/GNOME Shell stalled (mouse pointer didn't even move) for some minutes until swap was exhausted and evolution ran into a SIGSEGV (that one time I was patient enough to wait). This issue doesn't happen with the version in Fedora 23 GA, evolution-3.18.1-1.fc23.x86_64.

Version-Release number of selected component (if applicable):
evolution-3.18.2-1.fc23.x86_64


How reproducible:
Reproducible

Steps to Reproduce:
1. Start evolution, optionally configure a mail account
2. "New" (mail message)
3. Put in a recipient, subject
4. "Insert" -> "Text file..." -> (the attached evolution-send-broken.txt)
5. "Send" (or Ctrl+Return), confirm

Actual results:
Evolution allocates memory in a loop, eventually exhausting it if not killed/interrupted. The mail isn't sent at that point, nor appended to the sent mail folder.

Expected results:
Evolution sends the mail.

Additional info:
Here's what dmesg had to say about the segfault when memory ran out:

[12029.780328] evolution[21772]: segfault at bbadbeef ip 00007f0c5c53357c sp 00007ffe1592b9e0 error 6 in libjavascriptcoregtk-3.0.so.0.16.17[7f0c5bf42000+714000]

I could observe the phenomenon on my work machine (up-to-date, with many packages installed), as well as a newly setup Fedora 23 Workstation VM (installed via network, default pkg selection), with only evolution (and its dependencies) updated.