# CVE-2025-68480: marshmallow DoS — Fixed in 3.26.2

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

# CVE-2025-68480 — marshmallow

MEDIUM [Fix: marshmallow-code/marshmallow@d24a0c9](https://github.com/marshmallow-code/marshmallow/commit/d24a0c9df061c4daa92f71cf85aca25b83eee508)

CVE-2025-68480 is a medium-severity (CVSS 5.3) CWE-405 vulnerability in marshmallow. A fix is available for marshmallow — see the affected versions and patch details below.

Marshmallow has DoS in Schema.load(many)

Also known as[GHSA-428g-f7cq-pgp5](/vulnerability/GHSA-428g-f7cq-pgp5)PYSEC-2026-1605

Published

Dec 22, 2025

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

## Exploitation Status

### No confirmed exploitation observed yet

-   CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
-   CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-68480.

## EPSS Exploitation Probability

[via FIRST.org ↗](https://www.first.org/epss/)

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

0.00%0.27%0.53%0.80%0.1%0.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).

## How urgent is this, really

## Where this sits among everything scored

## Real-World Exposure

2 pkgs affected

🐍`marshmallow`🐍`marshmallow`

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

## Description

Marshmallow is a lightweight library for converting complex objects to and from simple Python datatypes. In versions from 3.0.0rc1 to before 3.26.2 and from 4.0.0 to before 4.1.2, Schema.load(data, many=True) is vulnerable to denial of service attacks. A moderately sized request can consume a disproportionate amount of CPU time. This issue has been patched in version 3.26.2 and 4.1.2.

## Affected Packages

2 total 2 fixed

Ecosystem

Package

Vulnerable range

Fix

🐍PyPI

`marshmallow` 

≥ 3.0.0rc1&&< 3.26.2

3.26.2`pip install --upgrade 'marshmallow==3.26.2'`

🐍PyPI

`marshmallow` 

≥ 4.0.0&&< 4.1.2

4.1.2`pip install --upgrade 'marshmallow==4.1.2'`

## Detection & mitigation playbook

Open-source dependency

1.  ### Detect
    
    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for marshmallow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
    
2.  ### Fix
    
    Update marshmallow to 3.26.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-68480 is resolved across your whole dependency graph.
    
3.  ### Workarounds
    
    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
    

## Frequently Asked Questions

Marshmallow is a lightweight library for converting complex objects to and from simple Python datatypes. In versions from 3.0.0rc1 to before 3.26.2 and from 4.0.0 to before 4.1.2, Schema.load(data, many=True) is vulnerable to denial of service attacks. A moderately sized request can consume a disproportionate amount of CPU time. This issue has been patched in version 3.26.2 and 4.1.2.

O3 Security · Impact-Aware SCA

### Is CVE-2025-68480 in your dependencies?

Find it across PyPI, including transitive dependencies.

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