Vulnerability CVE-2020-7212: Information

Description

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).

Severity: HIGH (7.5) Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Fixed packages

References to Advisories, Solutions, and Tools

1. Affected configurations:

   1. Configuration 1

      cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*

      Start including

      1.25.2

      End including

      1.25.7

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