CVE-2021-43528

6.5 mediumEPSS 1.3%

Medium (6.5). EPSS 1.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

6.5 medium

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

EPSS: 1.3% chance of exploitation in the next 30 days; higher than 70% of CVEs (scores of 2026-10-31)
CWE: CWE-269
Published: 2021-12-08
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

debian:debian_linux
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1742579
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html
https://security.gentoo.org/glsa/202208-14
https://www.debian.org/security/2022/dsa-5034
https://www.mozilla.org/security/advisories/mfsa2021-54/

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