What’s Vulnerable › Vulnerabilities

CVE-2021-43528

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-08 · updated 2026-06-17
• Weakness: CWE-269

Description

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.

Affected products

• Debian Linux: 9.0, 10.0, 11.0
• Mozilla Thunderbird: before 91.4.0 — fixed in 91.4.0

How to fix

Upgrade to a fixed version: Mozilla Thunderbird 91.4.0. Check the vendor advisory for mitigations.

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/
• 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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