Ecosyste.ms: Advisories

Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWhtdjItNzlxOC1mdjZn

Uncontrolled Resource Consumption in urllib3

The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denial of service (CPU consumption) because of an inefficient algorithm. The percent_encodings array contains all matches of percent encodings. It is not deduplicated. For a URL of length N, the size of percent_encodings may be up to O(N). The next step (normalize existing percent-encoded bytes) also takes up to O(N) for each step, so the total time is O(N^2). If percent_encodings were deduplicated, the time to compute _encode_invalid_chars would be O(kN), where k is at most 484 ((10+6*2)^2).

Permalink: https://github.com/advisories/GHSA-hmv2-79q8-fv6g
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWhtdjItNzlxOC1mdjZn
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: almost 3 years ago
Updated: about 1 year ago

CVSS Score: 7.5
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Identifiers: GHSA-hmv2-79q8-fv6g, CVE-2020-7212
References:

• https://nvd.nist.gov/vuln/detail/CVE-2020-7212
• https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e0221a
• https://github.com/urllib3/urllib3/blob/master/CHANGES.rst
• https://pypi.org/project/urllib3/1.25.8/
• https://github.com/advisories/GHSA-hmv2-79q8-fv6g

Repository: https://github.com/urllib3/urllib3
Blast Radius: 42.2

Affected Packages