Several security issues were fixed in Thunderbird.
- thunderbird: Mozilla Open Source mail and newsgroup client
Multiple security issues were discovered in Thunderbird. If a user were
tricked in to opening a specially crafted website in a browsing-like
context, an attacker could potentially exploit these to bypass same-origin
restrictions, cause a denial of service via application crash, or execute
arbitrary code. (CVE-2017-7826, CVE-2017-7828, CVE-2017-7830)
The problem can be corrected by updating your system to the following