USN-4701-1: Thunderbird vulnerabilities

20 January 2021

Several security issues were fixed in Thunderbird.



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Multiple security issues were discovered in Thunderbird. If a user were
tricked in to opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, bypass the CSS sanitizer, or execute
arbitrary code. (CVE-2020-16042, CVE-2020-16044, CVE-2020-26971,
CVE-2020-26973, CVE-2020-26974, CVE-2020-26978, CVE-2020-35113)

It was discovered that the proxy.onRequest API did not catch
view-source URLs. If a user were tricked in to installing an
extension with the proxy permission and opening View Source, an
attacker could potentially exploit this to obtain sensitive
information. (CVE-2020-35111)

A stack overflow was discovered due to incorrect parsing of SMTP server
response codes. An attacker could potentially exploit this to execute
arbitrary code. (CVE-2020-26970)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 20.10

After a standard system update you need to restart Thunderbird to make
all the necessary changes.

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