CVE-2026-87975 — Privilege abuse in model formsets with editable primary keys
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+2
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Djangoproject Django).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Djangoproject | Django | ≥ 6.1 and < 6.1.2≥ 6.0 and < 6.0.9≥ 5.2 and < 5.2.18 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.3 | CVSS 4.0 | Medium | — | — | 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92 via NIST National Vulnerability Database |
| 5.3 | CVSS 4.0 | Medium | — | — | DSF via CVE Program (cve.org) e CISA ADP |
| 4.3 | CVSS 3.1 | Medium | 2.8 | 1.4 | 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92 via NIST National Vulnerability Database |
| 4.3 | CVSS 3.1 | Medium | — | — | DSF via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N (score shown at the top: 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CWE-639 · Authorization Bypass Through User-Controlled Key (IDOR)
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.24%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Audit administrative actions and access to resources outside each user’s normal pattern.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · djangoproject/django
- SSVC assessment updated
- Record published
- CVSS changed · 4.3
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
7 on the record
- github.com/django/django/commit/ff27883ca055aa9ab23015b50674a5b10dfe5a41
- github.com/django/django/commit/cce6c57ed30ea83725f9d6abb2fe5ee932bab107
- github.com/django/django/commit/b83ab92bc5474558b083a840ea4628b3261b2cfe
- github.com/django/django/commit/83cbd21be57483e6b3eb6e4688a561c841aff75e
- docs.djangoproject.com/en/dev/releases/security/
- groups.google.com/g/django-announce
- www.djangoproject.com/weblog/2026/oct/06/security-releases/
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-87890 Potential request forgery via spatial lookup byte values 9d
- Medium CVE-2026-84429 Potential denial-of-service vulnerability in HTTP header parsing 9d
- Medium CVE-2026-77050 Potential denial-of-service vulnerability in get_supported_language_variant() 9d
- Medium CVE-2026-15337 An issue was discovered in Django 5.2 before 5.2.17 and 6.0 before 6.0.8… Aug 4, 2026
- High CVE-2026-15307 An issue was discovered in Django 5.2 before 5.2.17 and 6.0 before 6.0.8. GeoDjango… Aug 4, 2026
- Medium CVE-2026-15830 Potential denial-of-service vulnerability via nested geometry collections Aug 4, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-87975 is "Privilege abuse in model formsets with editable primary keys", rated Medium. It affects Django (Djangoproject); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.3 describes technical severity. EPSS 0.24% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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