CVE-2021-43529

9.8 criticalEPSS 0.5%

Critical (9.8) in mozilla thunderbird. EPSS 0.5% chance of exploitation in the next 30 days.

Thunderbird versions prior to 91.3.0 are vulnerable to the heap overflow described in CVE-2021-43527 when processing S/MIME messages. Thunderbird versions 91.3.0 and later will not call the vulnerable code when processing S/MIME messages that contain certificates with DER-encoded DSA or RSA-PSS signatures.

Severity

CVSS 3.1

9.8 critical

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

EPSS: 0.5% chance of exploitation in the next 30 days; higher than 40% of CVEs (scores of 2026-10-31)
CWE: CWE-787
Published: 2023-02-16
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2021-43529
https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2021-43529

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