A Thunderbird security update has been released for Ubuntu Linux 18.04 LTS and 20.04 LTS.

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Ubuntu Security Notice USN-5248-1
January 21, 2022

thunderbird vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in Thunderbird.

Software Description:
- thunderbird: Mozilla Open Source mail and newsgroup client

Details:

Multiple security issues were discovered in Thunderbird. If a user were
tricked into opening a specially crafted website in a browsing context, an
attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, trick a user into accepting unwanted
permissions, conduct header splitting attacks, conduct spoofing attacks,
bypass security restrictions, confuse the user, or execute arbitrary code.
(CVE-2021-4129, CVE-2021-4140, CVE-2021-29981, CVE-2021-29982,
CVE-2021-29987, CVE-2021-29991, CVE-2021-38495, CVE-2021-38496,
CVE-2021-38497, CVE-2021-38498, CVE-2021-38500, CVE-2021-38501,
CVE-2021-38503, CVE-2021-38504, CVE-2021-38506, CVE-2021-38507,
CVE-2021-38508, CVE-2021-38509, CVE-2021-43534, CVE-2021-43535,
CVE-2021-43536, CVE-2021-43537, CVE-2021-43538, CVE-2021-43539,
CVE-2021-43541, CVE-2021-43542, CVE-2021-43543, CVE-2021-43545,
CVE-2021-43656, CVE-2022-22737, CVE-2022-22738, CVE-2022-22739,
CVE-2022-22740, CVE-2022-22741, CVE-2022-22742, CVE-2022-22743,
CVE-2022-22745, CVE-2022-22747, CVE-2022-22748, CVE-2022-22751)

It was discovered that Thunderbird ignored the configuration to require
STARTTLS for an SMTP connection. A person-in-the-middle could potentially
exploit this to perform a downgrade attack in order to intercept messages
or take control of a session. (CVE-2021-38502)

It was discovered that JavaScript was unexpectedly enabled in the
composition area. An attacker could potentially exploit this in
combination with another vulnerability, with unspecified impacts.
(CVE-2021-43528)

A buffer overflow was discovered in the Matrix chat library bundled with
Thunderbird. An attacker could potentially exploit this to cause a denial
of service, or execute arbitrary code. (CVE-2021-44538)

It was discovered that Thunderbird's OpenPGP integration only considered
the inner signed message when checking signature validity in a message
that contains an additional outer MIME layer. An attacker could
potentially exploit this to trick the user into thinking that a message
has a valid signature. (CVE-2021-4126)

Update instructions:

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

Ubuntu 20.04 LTS:
thunderbird 1:91.5.0+build1-0ubuntu0.20.04.1

Ubuntu 18.04 LTS:
thunderbird 1:91.5.0+build1-0ubuntu0.18.04.1

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

References:
  https://ubuntu.com/security/notices/USN-5248-1
CVE-2021-29981, CVE-2021-29982, CVE-2021-29987, CVE-2021-29991,
CVE-2021-38495, CVE-2021-38496, CVE-2021-38497, CVE-2021-38498,
CVE-2021-38500, CVE-2021-38501, CVE-2021-38502, CVE-2021-38503,
CVE-2021-38504, CVE-2021-38506, CVE-2021-38507, CVE-2021-38508,
CVE-2021-38509, CVE-2021-4126, CVE-2021-4129, CVE-2021-4140,
CVE-2021-43528, CVE-2021-43534, CVE-2021-43535, CVE-2021-43536,
CVE-2021-43537, CVE-2021-43538, CVE-2021-43539, CVE-2021-43541,
CVE-2021-43542, CVE-2021-43543, CVE-2021-43545, CVE-2021-43546,
CVE-2021-44538, CVE-2022-22737, CVE-2022-22738, CVE-2022-22739,
CVE-2022-22740, CVE-2022-22741, CVE-2022-22742, CVE-2022-22743,
CVE-2022-22745, CVE-2022-22747, CVE-2022-22748, CVE-2022-22751

Package Information:

  https://launchpad.net/ubuntu/+source/thunderbird/1:91.5.0+build1-0ubuntu0.20.04.1

  https://launchpad.net/ubuntu/+source/thunderbird/1:91.5.0+build1-0ubuntu0.18.04.1