In marshmallow library the schema "only" option treats an empty list as implying no "only" option
In the marshmallow library before 2.15.1 and 3.x before 3.0.0b9 for Python, the schema "only" option treats an empty list as implying no "only" option, which allows a request that was intended to expose no fields to instead expose all fields (if the schema is being filtered dynamically using the "only" option, and there is a user role that produces an empty value for "only").
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | marshmallow | < 2.15.1, >= 3.0a0, < 3.0.0b9 | 2.15.1, 3.0.0b9 |
References
- https://github.com/marshmallow-code/marshmallow/pull/782
- https://github.com/marshmallow-code/marshmallow/pull/777
- https://github.com/marshmallow-code/marshmallow/issues/772
- https://github.com/advisories/GHSA-9q2p-fj49-vpxj
- https://nvd.nist.gov/vuln/detail/CVE-2018-17175
- https://github.com/marshmallow-code
- https://github.com/pypa/advisory-database/tree/main/vulns/marshmallow/PYSEC-2018-67.yaml
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-358- Platform
- Python (PyPI)
- Package
marshmallow- Disclosed
- 18.09.2018
- Updated
- 11.10.2026 11:20
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2018-67 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-9q2p-fj49-vpxj - CC BY 4.0
Vulnerability history: marshmallow
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 09.2018 12.2025
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 2
Disclosures per year
- 2018: 1
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 0
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In marshmallow library the schema "only" option treats an empty list as implying no "only" option this entry
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