CVE-2021-33503 – urllib3

Package

Manager: pip
Name: urllib3
Vulnerable Version: <1.26.5

Severity

Level: High

CVSS v3.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

EPSS: 0.00863 pctl0.74223

Details

Catastrophic backtracking in URL authority parser when passed URL containing many @ characters ### Impact When provided with a URL containing many `@` characters in the authority component the authority regular expression exhibits catastrophic backtracking causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect. ### Patches The issue has been fixed in urllib3 v1.26.5. ### References - [CVE-2021-33503](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-33503) - [JVNVU#92413403 (English)](https://jvn.jp/en/vu/JVNVU92413403/) - [JVNVU#92413403 (Japanese)](https://jvn.jp/vu/JVNVU92413403/) - [urllib3 v1.26.5](https://github.com/urllib3/urllib3/releases/tag/1.26.5) ### For more information If you have any questions or comments about this advisory: * Ask in our [community Discord](https://discord.gg/urllib3) * Email [sethmichaellarson@gmail.com](mailto:sethmichaellarson@gmail.com)

Metadata

Created: 2021-06-01T21:19:32Z
Modified: 2024-11-18T22:43:15Z
Source: MANUAL
CWE IDs: ["CWE-400"]
Alternative ID: GHSA-q2q7-5pp4-w6pg
Finding: F002
Auto approve: 1