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CVE-2020-7212

Publication date 6 March 2020

Last updated 24 July 2024


Ubuntu priority

Cvss 3 Severity Score

7.5 · High

Score breakdown

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).

Read the notes from the security team

Status

Package Ubuntu Release Status
python-urllib3 20.04 LTS focal
Not affected
19.10 eoan
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected

Notes


leosilva

Introduced by a74c9cfbaed9f811e7563cfc3dce894928e0221a fixed by a2697e7c6b275f05879b60f593c5854a816489f0 Introduced in 1.25.2 and fixed in 1.25.8

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
python-urllib3

Severity score breakdown

Parameter Value
Base score 7.5 · High
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H