Vulnerability · Published Jun 3, 2026 · Assigned by DSF
CVE-2026-7666Potential unencrypted email transmission via STARTTLS in the SMTP backend
Low 3.1
In plain English
A low-severity security flaw in Django from djangoproject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | py3-django | 5.2.15-r0 | ALPINE-CVE-2026-7666 |
| Debian:12 | python-django | no fix listed | DEBIAN-CVE-2026-7666 |
| Debian:13 | python-django | no fix listed | DEBIAN-CVE-2026-7666 |
| Debian:14 | python-django | 3:5.2.15-1 | DEBIAN-CVE-2026-7666 |
| PyPI | django | 5.2.15, 6.0.6 | PYSEC-2026-200 |
| PyPI | django | 5.2.15 | GHSA-mm6v-q8q9-pgcf |
| PyPI | django | 6.0.6 | GHSA-mm6v-q8q9-pgcf |
| Ubuntu:22.04:LTS | python-django | no fix listed | UBUNTU-CVE-2026-7666 |
| Ubuntu:24.04:LTS | python-django | no fix listed | UBUNTU-CVE-2026-7666 |
| Ubuntu:25.10 | python-django | no fix listed | UBUNTU-CVE-2026-7666 |
| Ubuntu:26.04:LTS | python-django | no fix listed | UBUNTU-CVE-2026-7666 |
| Ubuntu:26.10 | python-django | no fix listed | UBUNTU-CVE-2026-7666 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| djangoproject | Django | 6.0 – before 6.0.65.2 – before 5.2.15 |
Weakness: CWE-319 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
References
- Django security archive vendor-advisory
- Django releases announcements mailing-list
- Django security releases issued: 6.0.6 and 5.2.15 vendor-advisory