Denial of Service in urllib3 Library Affecting Python Applications
CVE-2020-7212

7.5HIGH

Key Information:

Vendor

Python

Status
Urllib3
Vendor
CVE Published:
6 March 2020

What is CVE-2020-7212?

The _encode_invalid_chars function within the urllib3 library can lead to a denial of service due to an inefficient algorithm when processing percent-encoded characters. Specifically, the computation time grows quadratically with the length of the URL, as the function handles matches in the percent_encodings array without deduplication. In scenarios where a long URL is processed, the CPU consumption may spike, potentially causing service disruptions in applications relying on this library.

References

https://github.com/urllib3/urllib3/blob/master/CHANGES.rst
x_refsource_MISC
https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f81...
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https://pypi.org/project/urllib3/1.25.8/
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CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.