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).
                
            Metrics
Affected Vendors & Products
References
        History
                    No history.
 MITRE
                        MITRE
                    Status: PUBLISHED
Assigner: mitre
Published: 2020-03-06T19:14:54
Updated: 2024-08-04T09:25:48.318Z
Reserved: 2020-01-16T00:00:00
Link: CVE-2020-7212
 Vulnrichment
                        Vulnrichment
                    No data.
 NVD
                        NVD
                    Status : Modified
Published: 2020-03-06T20:15:12.707
Modified: 2024-11-21T05:36:50.467
Link: CVE-2020-7212
 Redhat
                        Redhat