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).

CVSS v3 7.5 HIGH
CVSS v2.0 7.8 HIGH

7.5^/10

CVSS v3 : HIGH

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

7.8^/10

CVSS v2.0 : HIGH

Vector : AV:N/AC:L/Au:N/C:N/I:N/A:C

Exploitability : 10.0 / Impact : 6.9

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact COMPLETE

References

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

Configurations

Configuration 1 (hide)

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

History

No history.

Information

Published : 2020-03-06 20:15

Updated : 2023-12-10 13:13

NVD link : CVE-2020-7212

Mitre link : CVE-2020-7212

CVE.ORG link : CVE-2020-7212

JSON object : View

Products Affected

python

urllib3

CWE

CWE-400

Uncontrolled Resource Consumption

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