Vulnerability in Mozilla Thunderbird

CVE-2021-29969

If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker injected IMAP server responses prior to the completion of the STARTTLS handshake, then Thunderbird didn't ignore the injected data. This could have resulted in Thunderbird showing incorrect information, for example the attacker could have tricked Thunderbird to show folders that didn't exist on the IMAP server. This vulnerability affects Thunderbird < 78.12.

EPSS: 0.012 (65.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-29969?
CVE-2021-29969 is a medium-severity vulnerability in Mozilla Thunderbird, classified under Files or Directories Accessible to External Parties. CVSS score: 5.9/10. Published 2021-08-05.
How severe is CVE-2021-29969?
Medium severity. CVSS v3 base score is 5.9 out of 10.