CVE-2026-7666: CWE-319: Cleartext Transmission of Sensitive Information in djangoproject Django
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.
AI Analysis
Technical Summary
CVE-2026-7666 is a vulnerability in the django.core.mail.backends.smtp.EmailBackend component of Django versions 6.0 prior to 6.0.6 and 5.2 prior to 5.2.15. When the STARTTLS handshake fails and fail_silently=True is set, the backend may reuse a partially-initialized SMTP connection, allowing an on-path attacker to intercept email content transmitted in cleartext. This cleartext transmission of sensitive information corresponds to CWE-319. Earlier unsupported Django versions were not evaluated but may also be affected. No official remediation level or patch links are provided in the data.
Potential Impact
An attacker positioned on the network path can read email content sent via Django's SMTP backend if the STARTTLS handshake fails and fail_silently=True is configured. This compromises the confidentiality of email content but does not affect integrity or availability. The CVSS score of 3.1 (low) reflects that exploitation requires network access and user interaction, and the impact is limited to information disclosure.
Mitigation Recommendations
Patch status is not yet confirmed — check the official Django vendor advisory for current remediation guidance. Until a fix is confirmed, avoid using fail_silently=True with the SMTP EmailBackend or ensure that STARTTLS connections are reliably established. Monitor vendor communications for patches or official mitigations.
CVE-2026-7666: CWE-319: Cleartext Transmission of Sensitive Information in djangoproject Django
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.
CVSS v3.1
Score 3.1low
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-7666 is a vulnerability in the django.core.mail.backends.smtp.EmailBackend component of Django versions 6.0 prior to 6.0.6 and 5.2 prior to 5.2.15. When the STARTTLS handshake fails and fail_silently=True is set, the backend may reuse a partially-initialized SMTP connection, allowing an on-path attacker to intercept email content transmitted in cleartext. This cleartext transmission of sensitive information corresponds to CWE-319. Earlier unsupported Django versions were not evaluated but may also be affected. No official remediation level or patch links are provided in the data.
Potential Impact
An attacker positioned on the network path can read email content sent via Django's SMTP backend if the STARTTLS handshake fails and fail_silently=True is configured. This compromises the confidentiality of email content but does not affect integrity or availability. The CVSS score of 3.1 (low) reflects that exploitation requires network access and user interaction, and the impact is limited to information disclosure.
Mitigation Recommendations
Patch status is not yet confirmed — check the official Django vendor advisory for current remediation guidance. Until a fix is confirmed, avoid using fail_silently=True with the SMTP EmailBackend or ensure that STARTTLS connections are reliably established. Monitor vendor communications for patches or official mitigations.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- DSF
- Date Reserved
- 2026-05-01T19:59:31.353Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a2037c7e29bf47b50c14ee1
Added to database: 6/3/2026, 2:18:47 PM
Last enriched: 6/3/2026, 2:48:31 PM
Last updated: 6/4/2026, 4:59:44 AM
Views: 11
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