---
id: CVE-2021-41945
title: >-
  Encode OSS httpx < 0.23.0 is affected by improper input validation in
  `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.
summary: >-
  Encode OSS httpx < 0.23.0 is affected by improper input validation in
  `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-20
vendor: encode
product: httpx
affected:
  - httpx < 0.23.0
patched:
  - httpx 0.23.0
published: '2022-04-28'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-41945'
references:
  - url: 'https://gist.github.com/lebr0nli/4edb76bbd3b5ff993cf44f2fbce5e571'
    label: cve@mitre.org
  - url: 'https://github.com/encode/httpx'
    label: cve@mitre.org
  - url: 'https://github.com/encode/httpx/discussions/1831'
    label: cve@mitre.org
  - url: 'https://github.com/encode/httpx/issues/2184'
    label: cve@mitre.org
  - url: 'https://github.com/encode/httpx/releases/tag/0.23.0'
    label: cve@mitre.org
  - url: 'http://encode.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://gist.github.com/lebr0nli/4edb76bbd3b5ff993cf44f2fbce5e571'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/encode/httpx'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/encode/httpx/discussions/1831'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/encode/httpx/issues/2184'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/encode/httpx/releases/tag/0.23.0'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.02178
epssPercentile: 0.81576
ingestedAt: '2026-07-06T17:03:24.174Z'
---

## Overview

Encode OSS httpx < 0.23.0 is affected by improper input validation in `httpx.URL`, `httpx.Client` and some functions using `httpx.URL.copy_with`.

## Affected

- `httpx < 0.23.0`

## Remediation

Upgrade past the affected range:

- `httpx 0.23.0`