CVE-2026-27953
Collerek Ormar privilege escalation
- Published19 Mar 2026
Description
ormar is a async mini ORM for Python. Versions 0.23.0 and below are vulnerable to Pydantic validation bypass through the model constructor, allowing any unauthenticated user to skip all field validation by injecting "__pk_only__": true into a JSON request body. By injecting "__pk_only__": true into a JSON request body, an unauthenticated attacker can skip all field validation and persist unvalidated data directly to the database. A secondary __excluded__ parameter injection uses the same pattern to selectively nullify arbitrary model fields (e.g., email or role) during construction. This affects ormar's canonical FastAPI integration pattern recommended in its official documentation, enabling privilege escalation, data integrity violations, and business logic bypass in any application using ormar.Model directly as a request body parameter. This issue has been fixed in version 0.23.1.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:LAffected products
Remediation
- https://github.com/ormar-orm/ormar/blob/master/examples/fastapi_quick_start.py#L55
- https://github.com/ormar-orm/ormar/blob/master/ormar/fields/foreign_key.py#L41
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/helpers/pydantic.py#L108
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/model.py#L89
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/newbasemodel.py#L128
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/newbasemodel.py#L292
References
- https://github.com/ormar-orm/ormar/blob/master/examples/fastapi_quick_start.py#L55
- https://github.com/ormar-orm/ormar/blob/master/ormar/fields/foreign_key.py#L41
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/helpers/pydantic.py#L108
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/model.py#L89
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/newbasemodel.py#L128
- https://github.com/ormar-orm/ormar/blob/master/ormar/models/newbasemodel.py#L292
- https://github.com/ormar-orm/ormar/commit/7f22aa21a7614b993970345b392dabb0ccde0ab3
- https://github.com/ormar-orm/ormar/releases/tag/0.23.1
- https://github.com/ormar-orm/ormar/security/advisories/GHSA-f964-whrq-44h8
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-27953 being actively exploited?
CVE-2026-27953 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.91%.
How severe is CVE-2026-27953?
CVE-2026-27953 has a CVSS 3.1 base score of 7.1, rated high. EPSS estimates a 0.91% probability of exploitation.
Which products are affected by CVE-2026-27953?
Affected products include Collerek Ormar.
How do I fix CVE-2026-27953?
Upgrade affected software to a fixed version, for example Collerek Ormar 0.23.1 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-27953 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.