Vulnerability advisory

CVE-2026-7666

Potential unencrypted email transmission via STARTTLS in the SMTP backend

Published Jun 3, 2026Updated Oct 28, 2026OSV record ↗

Also known as BIT-django-2026-7666GHSA-mm6v-q8q9-pgcfPYSEC-2026-200

Severity

CVSS 4.0CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Affected versions

Repository

Affected commits	Fixed by commit
GIT github.com/django/django ↗
9e7cc2b628fe8fd3895986af9b7fc9525034c1b0 to before 21e98408f84d22191e2c7ee4052bdd12d264fd3f	`21e98408f84d22191e2c7ee4052bdd12d264fd3f`
36b5f39d9372147f0e758f590e35ee2b2bc317dd to before ee93f65169c280c9ab3d2ce103dd478c96d05065	`ee93f65169c280c9ab3d2ce103dd478c96d05065`
Also listed as affected (21) `5.2.14` `6.0.5` `5.2.13` `6.0.4` `5.2.12` `6.0.3` `5.2.11` `6.0.2` `6.0.1` `5.2.10` `6.0` `5.2.9` `5.2.8` `5.2.7` `5.2.6` `5.2.5` `5.2.4` `5.2.3` `5.2.2` `5.2.1` `5.2`

Description

An issue was discovered in Django 6.0 before 6.0.6 and 5.2 before 5.2.15. django.core.mail.backends.smtp.EmailBackend in Django fails to prevent reuse of a partially-initialized connection after a failed STARTTLS handshake when fail_silently=True, which allows on-path network attackers to read email content via cleartext interception. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Kasper Dupont for reporting this issue.

CVE-2026-7666

Affected versions

Repository

Description

References