Mozilla Thunderbird < 91.0

high Nessus Plugin ID 152503


A mail client installed on the remote Windows host is affected by multiple vulnerabilities.


The version of Thunderbird installed on the remote Windows host is prior to 91.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2021-36 advisory.

- A suspected race condition when calling getaddrinfo led to memory corruption and a potentially exploitable crash. Note: This issue only affected Linux operating systems. Other operating systems are unaffected. (CVE-2021-29986)

- An issue present in lowering/register allocation could have led to obscure but deterministic register confusion failures in JITted code that would lead to a potentially exploitable crash. (CVE-2021-29981)

- Thunderbird incorrectly treated an inline list-item element as a block element, resulting in an out of bounds read or memory corruption, and a potentially exploitable crash. (CVE-2021-29988)

- Instruction reordering resulted in a sequence of instructions that would cause an object to be incorrectly considered during garbage collection. This led to memory corruption and a potentially exploitable crash.

- Uninitialized memory in a canvas object could have caused an incorrect free() leading to memory corruption and a potentially exploitable crash. (CVE-2021-29980)

- After requesting multiple permissions, and closing the first permission panel, subsequent permission panels will be displayed in a different position but still record a click in the default location, making it possible to trick a user into accepting a permission they did not want to.This bug only affects Thunderbird on Linux. Other operating systems are unaffected. (CVE-2021-29987)

- A use-after-free vulnerability in media channels could have led to memory corruption and a potentially exploitable crash. (CVE-2021-29985)

- Due to incorrect JIT optimization, we incorrectly interpreted data from the wrong type of object, resulting in the potential leak of a single bit of memory. (CVE-2021-29982)

- Mozilla developers Kershaw Chang, Philipp, Chris Peterson, Sebastian Hengst, Christoph Kerschbaumer, Olli Pettay, Sandor Molnar, and Simon Giesecke reported memory safety bugs present in versions of Thunderbird prior to 91. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. (CVE-2021-29989)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Upgrade to Mozilla Thunderbird version 91.0 or later.

See Also

Plugin Details

Severity: High

ID: 152503

File Name: mozilla_thunderbird_91_0.nasl

Version: 1.3

Type: local

Agent: windows

Family: Windows

Published: 8/11/2021

Updated: 8/26/2021

Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent

Risk Information


Risk Factor: High

Score: 7.4


Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2021-29989


Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:mozilla:thunderbird

Required KB Items: Mozilla/Thunderbird/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 8/11/2021

Vulnerability Publication Date: 8/10/2021

Reference Information

CVE: CVE-2021-29980, CVE-2021-29981, CVE-2021-29982, CVE-2021-29984, CVE-2021-29985, CVE-2021-29986, CVE-2021-29987, CVE-2021-29988, CVE-2021-29989