Security Vulnerabilities fixed in Thunderbird 91.1 — Mozilla

2021-09-0700:00:00

Mozilla Foundation

www.mozilla.org

thunderbird

mozilla

security vulnerabilities

memory safety

memory corruption

unprivileged mode

internet explorer

windows

CVSS2

6.8

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS3

8.8

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

0.003

Percentile

70.0%

JSON

When delegating navigations to the operating system, Thunderbird would accept the mk scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. This bug only affects Thunderbird for Windows. Other operating systems are unaffected.
Mozilla developers Tyson Smith, Christian Holler, and Gabriele Svelto reported memory safety bugs present in Thunderbird 78.13.0. 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.