CVE-2026-87975

MEDIUM
Published Oct 6, 2026 Modified Oct 6, 2026 CWE-639

Description

An issue was discovered in Django 6.1 before 6.1.2, 6.0 before 6.0.9, and 5.2 before 5.2.18. `django.forms.models.BaseModelFormSet.save_existing_objects()` used the presence of a primary key on a submitted form's instance as evidence that the instance belonged to the formset's limiting queryset. An object outside that queryset is represented by a newly constructed instance whose primary key can still be populated from submitted data when the model's primary key is a field accepted by the form, such as a `OneToOneField` or parent link used as the primary key of an inline formset's model, or a natural or UUID primary key included in the form's fields. This allows an authenticated user permitted to submit such a formset to delete rows outside the limiting queryset, without any permission on the targeted object, via forged management-form data marking an out-of-queryset object for deletion. Models using the default AutoField primary key are not affected. Earlier, unsupported Django series (such as 5.1.x, 5.0.x, and 4.2.x) were not evaluated and may also be affected. Django would like to thank Seonggwon Yoon for reporting this issue.

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CVSS v3.1 Score

4.3
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0024
Probability of exploitation
0.14%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-639 CWE-639

References

Frequently Asked Questions

What is CVE-2026-87975? +
An issue was discovered in Django 6.1 before 6.1.2, 6.0 before 6.0.9, and 5.2 before 5.2.18. `django.forms.models.BaseModelFormSet.save_existing_objects()` used the presence of a primary key on a submitted form's instance as evidence that the instance belonged to the formset's limiting queryset. An object outside that queryset is represented by a newly constructed instance whose primary key can still be populated from submitted data when the model's primary key is a field accepted by the form, such as a `OneToOneField` or parent link used as the primary key of an inline formset's model, or a natural or UUID primary key included in the form's fields. This allows an authenticated user permitted to submit such a formset to delete rows outside the limiting queryset, without any permission on the targeted object, via forged management-form data marking an out-of-queryset object for deletion. Models using the default AutoField primary key are not affected. Earlier, unsupported Django series (such as 5.1.x, 5.0.x, and 4.2.x) were not evaluated and may also be affected. Django would like to thank Seonggwon Yoon for reporting this issue. It has a CVSS v3.1 base score of 4.3 (MEDIUM).
How severe is CVE-2026-87975? +
CVE-2026-87975 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-87975? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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