Description
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").
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-marshmallow | 3.0.0b14-1 | — |
| Debian 13 | python-marshmallow | 3.0.0b14-1 | — |
| Debian 12 | python-marshmallow | 3.0.0b14-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | python-marshmallow | 3.26.1-0.4ubuntu0.1~esm1 | USN-8225-1 |
| Ubuntu Pro 24.04 LTS | python-marshmallow | 3.20.1-1.1ubuntu0.1~esm1 | USN-8225-1 |
| Ubuntu Pro 22.04 LTS | python-marshmallow | 3.13.0-1ubuntu0.1~esm1 | USN-8225-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | python-marshmallow | 3.4.0-1ubuntu0.1~esm1 | USN-8225-1 |
| Ubuntu Pro 18.04 LTS | python-marshmallow | 3.0.0b3-1ubuntu0.1~esm1 | USN-8225-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-marshmallow | 3.20.2-2.2 | openSUSE-SU-2026:12017-1, openSUSE-SU-2024:14147-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | marshmallow | < 2.15.1 | 2.15.1 | GHSA-9q2p-fj49-vpxj |
| PyPI | marshmallow | >= 3.0a0, < 3.0.0b9 | 3.0.0b9 | GHSA-9q2p-fj49-vpxj |
| PyPI | marshmallow | < 2.15.1 · >= 3.0a0, < 3.0.0b9 | 2.15.1, 3.0.0b9 | PYSEC-2018-67 |
Advisories 3
- openSUSE-SU-2026:12017-1 python313-marshmallow-4.3.0-1.2 on GA media SUSE / openSUSE Security Updates · Oct 5, 2026
- USN-8225-1 python-marshmallow vulnerabilities Ubuntu Security Notices (USN) · Apr 30, 2026
- openSUSE-SU-2024:14147-1 python-marshmallow-doc-3.20.2-2.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026