CVE-2021-38502

high
Published — · Modified —
CVSS v3
CVSS v2
VIR risk
8.0

Description

Thunderbird ignored the configuration to require STARTTLS security for an SMTP connection. A MITM could perform a downgrade attack to intercept transmitted messages, or could take control of the authenticated session to execute SMTP commands chosen by the MITM. If an unprotected authentication method was configured, the MITM could obtain the authentication credentials, too. This vulnerability affects Thunderbird < 91.2.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-38502

vendor Authored 2026-05-27

Vendor advisory: rocky — https://errata.rockylinux.org/RLSA-2021:3838

OS impact

OSVersionStatusFixed in
arch archfixed91.2.0-1
rockylinux rocky8fixed
debian debianbookwormfixed1:91.2.1-1
debian debianbullseyefixed1:91.4.1-1~deb11u1
debian debianforkyfixed1:91.2.1-1
debian debiansidfixed1:91.2.1-1
debian debiantrixiefixed1:91.2.1-1

References

Verify integrity in audit chain (admin only). AS-IS.