CVE-2026-7666: CWE-319: Cleartext Transmission of Sensitive Information in djangoproject Django
A vulnerability in Django's SMTP email backend allows an on-path attacker to intercept email content in cleartext if a STARTTLS handshake fails and the connection is reused with fail_silently=True. This affects Django versions 6.0 and 5.2. The issue arises because the backend does not prevent reuse of a partially-initialized connection after a failed STARTTLS attempt. The severity is rated low with a CVSS score of 3.1.
AI Analysis
Technical Summary
CVE-2026-7666 describes a vulnerability in Django's django.core.mail.backends.smtp.EmailBackend where, if the STARTTLS handshake fails and fail_silently=True is set, the backend may reuse a partially-initialized SMTP connection. This allows an on-path network attacker to read email content transmitted in cleartext. The issue affects Django versions 6.0 before 6.0.6 and 5.2 before 5.2.15. Earlier unsupported versions were not evaluated and may also be affected. No official remediation level or patch links are provided in the available data.
Potential Impact
An attacker positioned on the network path can intercept and read email content sent via Django's SMTP backend if the STARTTLS handshake fails and fail_silently=True is configured. This leads to cleartext exposure of sensitive information in emails. The impact is limited to confidentiality and does not affect integrity or availability. The CVSS score of 3.1 reflects a low severity due to the conditions required for exploitation and limited impact scope.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid using fail_silently=True with the SMTP email backend or ensure that STARTTLS handshakes succeed to prevent fallback to cleartext transmission. Monitor vendor communications for updates and apply patches once released.
CVE-2026-7666: CWE-319: Cleartext Transmission of Sensitive Information in djangoproject Django
Description
A vulnerability in Django's SMTP email backend allows an on-path attacker to intercept email content in cleartext if a STARTTLS handshake fails and the connection is reused with fail_silently=True. This affects Django versions 6.0 and 5.2. The issue arises because the backend does not prevent reuse of a partially-initialized connection after a failed STARTTLS attempt. The severity is rated low with a CVSS score of 3.1.
CVSS v3.1
Score 3.1low
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-7666 describes a vulnerability in Django's django.core.mail.backends.smtp.EmailBackend where, if the STARTTLS handshake fails and fail_silently=True is set, the backend may reuse a partially-initialized SMTP connection. This allows an on-path network attacker to read email content transmitted in cleartext. The issue affects Django versions 6.0 before 6.0.6 and 5.2 before 5.2.15. Earlier unsupported versions were not evaluated and may also be affected. No official remediation level or patch links are provided in the available data.
Potential Impact
An attacker positioned on the network path can intercept and read email content sent via Django's SMTP backend if the STARTTLS handshake fails and fail_silently=True is configured. This leads to cleartext exposure of sensitive information in emails. The impact is limited to confidentiality and does not affect integrity or availability. The CVSS score of 3.1 reflects a low severity due to the conditions required for exploitation and limited impact scope.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid using fail_silently=True with the SMTP email backend or ensure that STARTTLS handshakes succeed to prevent fallback to cleartext transmission. Monitor vendor communications for updates and apply patches once released.
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: 06/03/2026, 14:18:47 UTC
Last enriched: 07/14/2026, 10:00:27 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 96
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