OrmarApplication · Collerek
CVE-2026-27953
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedormar 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe ormar async ORM for Python versions 0.23.0 and below allows attackers to bypass Pydantic field validation by injecting '__pk_only__: true' into JSON request bodies, persisting unvalidated data directly to the database. A secondary '__excluded__' parameter enables nullifying arbitrary fields like email or role during model construction.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
OrmarApplication
< 0.23.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify ormar library versionRun 'pip show ormar' or check your requirements.txt/poetry.lock file for the installed ormar package versionAffected if The installed version is below 0.23.1 (e.g., 0.23.0, 0.22.0, etc.)
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Find FastAPI endpoints using ormar.Model as request bodySearch your codebase for FastAPI route definitions (e.g., @app.post, @app.put) where the request body type is set directly to an ormar.Model class (e.g., 'body: MyOrmarModel')Affected if Any endpoint accepts ormar.Model as the direct request body parameter type without an intermediate Pydantic model
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Inspect JSON request body handlingReview the endpoint handler code to see if the incoming JSON request body is passed directly to ormar methods like .save(), .create(), or .update() without prior validationAffected if JSON data from requests is persisted via ormar without passing through a Pydantic model validation layer first
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Check for __pk_only__ and __excluded__ parameter handlingSearch your codebase or API logs for any usage or attempted injection of '__pk_only__' or '__excluded__' parameters in JSON request bodies to endpoints using ormar.ModelAffected if These special parameters can be sent in requests and are processed by ormar, bypassing normal field validation
You are affected if your application uses ormar version below 0.23.1 AND has FastAPI endpoints that accept ormar.Model directly as request body parameters without an intermediate Pydantic validation layer.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.23.1
Upgrade ormar to version 0.23.1 or later to patch the validation bypass vulnerability.
0.23.1 or later
- Upgrade ormar to version 0.23.1 or later using pip: pip install ormar>=0.23.1
- Verify the upgrade was successful by checking the installed version: pip show ormar
- Test that FastAPI endpoints using ormar.Model as request body parameters now properly validate all fields
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ormar
Scoped from the published advisory
- Consultation4.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,160.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-27953 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-27953 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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