CVE-2026-7666 Potential unencrypted email transmission via STARTTLS in the SMTP backend
On-path attackers can read email content in cleartext if Django's SMTP backend reuses a failed STARTTLS connection with fail_silently enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-7666?
CVE-2026-7666 is a low-severity vulnerability in Djangoproject Django, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-319
Which versions are affected by CVE-2026-7666?
6 open source packages ship an affected version, including django. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
django Bitnami | From 5.2.0 | 5.2.15, 6.0.6 |
django PyPI | From 5.2 | 5.2.15, 6.0.6 |
django PyPI | From 5.2 | 5.2.15 |
django PyPI | From 5.2 | 5.2.15 |
django PyPI | From 6.0 | 6.0.6 |
django PyPI | From 6.0 | 6.0.6 |
Products include Djangoproject Django.
How do I fix CVE-2026-7666?
Upgrade django to a fixed version for your release line: 5.2.15 or 6.0.6.
Is CVE-2026-7666 being exploited?
There is no known exploitation of CVE-2026-7666 in the wild and no public exploit code.
Other vulnerabilities in Djangoproject Django
- CVE-2026-4277 Privilege abuse in GenericInlineModelAdmin
- CVE-2024-53908 Django SQL injection in HasKey(lhs, rhs) on Oracle
- CVE-2024-42005 Django SQL injection vulnerability
- CVE-2023-31047 Django bypasses validation when using one form field to upload multiple files
- CVE-2022-34265 Django `Trunc()` and `Extract()` database functions vulnerable to SQL Injection
Sources
Also known as BIT-django-2026-7666, DEBIAN-CVE-2026-7666, ECHO-45a8-c123-8d52, GHSA-mm6v-q8q9-pgcf, MINI-j4g8-q4fh-c38c, PYSEC-2026-200 and 1 more.