Thunderbird unexpectedly enabled JavaScript in the composition area. The JavaScript execution context was limited to this area and did not receive chrome-level privileges, but could be used as a stepping stone to further an attack with other vulnerabilities. This vulnerability affects Thunderbird < 91.4.0.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-43528
• https://bugzilla.mozilla.org/show_bug.cgi?id=1742579
• https://www.mozilla.org/security/advisories/mfsa2021-54/
• https://www.debian.org/security/2022/dsa-5034
• https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html
• https://security.gentoo.org/glsa/202208-14