---
id: CVE-2020-15225
aliases:
  - GHSA-x7gm-rfgv-w973
  - PYSEC-2021-64
title: Potential DoS with NumberFilter conversion to integer values.
summary: Potential DoS with NumberFilter conversion to integer values.
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: django-filter
product: django-filter
ecosystem: pip
affected:
  - django-filter < 2.4.0
patched:
  - django-filter 2.4.0
published: '2020-09-28'
updated: '2026-07-08'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-x7gm-rfgv-w973'
references:
  - url: >-
      https://github.com/carltongibson/django-filter/security/advisories/GHSA-x7gm-rfgv-w973
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2020-15225'
  - url: >-
      https://github.com/carltongibson/django-filter/commit/340cf7a23a2b3dcd7183f6a0d6c383e85b130d2b
  - url: 'https://github.com/carltongibson/django-filter'
  - url: 'https://github.com/carltongibson/django-filter/releases/tag/2.4.0'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/django-filter/PYSEC-2021-64.yaml
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DPHENTRHRAYFXYPPBT7JRHZRWILRY44S
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FAT2ZAEF6DM3VFSOHKB7X3ASSHGQHJAK
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SVJ7AYU6FUSU3F653YCGW5LFD3IULRSX
  - url: 'https://pypi.org/project/django-filter'
  - url: 'https://security.netapp.com/advisory/ntap-20210604-0010'
tags:
  - osv
  - pip
epss: 0.01797
epssPercentile: 0.77491
ingestedAt: '2026-07-08T18:25:54.137Z'
---

## Overview

### Impact

Automatically generated `NumberFilter` instances, whose value was later converted to an integer, were subject to potential DoS from maliciously input using exponential format with sufficiently large exponents. 

### Patches

Version 2.4.0+ applies a `MaxValueValidator` with a a default `limit_value` of 1e50 to the form field used by `NumberFilter` instances. 

In addition, `NumberFilter` implements the new `get_max_validator()` which should return a configured validator instance to customise the limit, or else `None` to disable the additional validation. 

### Workarounds

Users may manually apply an equivalent validator if they are not able to upgrade.  

### For more information
If you have any questions or comments about this advisory:
* Open an issue in [the django-filter repo](https://github.com/carltongibson/django-filter)

Thanks to Marcin Waraksa for the report. 


## Affected packages

- `django-filter < 2.4.0`

## Remediation

Upgrade to a patched release:

- `django-filter 2.4.0`