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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.

PUBLISHED Reserved 2026-05-01 | Published 2026-06-03 | Updated 2026-06-03 | Assigner DSF




LOW: 3.1CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
LOW: 2.3CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-319: Cleartext Transmission of Sensitive Information

Product status

Default status
unaffected

6.0 (python) before 6.0.6
affected

6.0.6 (python)
unaffected

5.2 (python) before 5.2.15
affected

5.2.15 (python)
unaffected

Timeline

2026-04-22:Initial report received.
2026-05-12:Vulnerability confirmed.
2026-06-03:Security release issued.

Credits

Kasper Dupont reporter

Jake Howard remediation developer

Natalia Bidart coordinator

References

docs.djangoproject.com/en/dev/releases/security/ (Django security archive) vendor-advisory

groups.google.com/g/django-announce (Django releases announcements) mailing-list

www.djangoproject.com/weblog/2026/jun/03/security-releases/ (Django security releases issued: 6.0.6 and 5.2.15) vendor-advisory

cve.org (CVE-2026-7666)

nvd.nist.gov (CVE-2026-7666)

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