CVE-2020-7212

Published Mar 6, 2020

Last updated 5 years ago

Overview

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).
Source: cve@mitre.org
NVD status: Analyzed

Hype score: Not currently trending

Risk scores

CVSS 3.1

Type: Primary
Base score: 7.5
Impact score: 3.6
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: HIGH

CVSS 2.0

Type: Primary
Base score: 7.8
Impact score: 6.9
Exploitability score: 10
Vector string: AV:N/AC:L/Au:N/C:N/I:N/A:C

Weaknesses

nvd@nist.gov: CWE-400

Configurations

[
  {
    "nodes": [
      {
        "negate": false,
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*",
            "vulnerable": true,
            "matchCriteriaId": "C6E2E571-FF01-4577-BEE4-CD2F2448A06E",
            "versionEndIncluding": "1.25.7",
            "versionStartIncluding": "1.25.2"
          }
        ],
        "operator": "OR"
      }
    ]
  }
]

Overview

Social media

Risk scores

CVSS 3.1

CVSS 2.0

Weaknesses

Configurations

References