CVE Vulnerability

CVE-2020-7212

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).

7.8 /10

CVSS v2.0 :

V3 Legend

Vector :

Exploitability : 10 / Impact : 6.9

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact COMPLETE

Scope

7.5 /10

CVSS v3.0 : HIGH

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://github.com/urllib3/urllib3/blob/master/CHANGES.rst Release Notes Third Party Advisory
https://pypi.org/project/urllib3/1.25.8/ Release Notes Vendor Advisory
https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e0221a Patch Third Party Advisory
Configurations

Configuration 1

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

Published : 2020-03-06 08:15

Updated : 2020-03-09 04:55

NVD link : CVE-2020-7212

Mitre link : CVE-2020-7212

Products Affected
No products.
CWE
CWE-400