Vulnerability Description
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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Python | Urllib3 | >= 1.25.2, <= 1.25.7 |
Related Weaknesses (CWE)
References
- https://github.com/urllib3/urllib3/blob/master/CHANGES.rstRelease NotesThird Party Advisory
- https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e022PatchThird Party Advisory
- https://pypi.org/project/urllib3/1.25.8/Release NotesVendor Advisory
- https://github.com/urllib3/urllib3/blob/master/CHANGES.rstRelease NotesThird Party Advisory
- https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e022PatchThird Party Advisory
- https://pypi.org/project/urllib3/1.25.8/Release NotesVendor Advisory
FAQ
What is CVE-2020-7212?
CVE-2020-7212 is a vulnerability with a CVSS score of 7.5 (HIGH). 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_...
How severe is CVE-2020-7212?
CVE-2020-7212 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-7212?
Check the references section above for vendor advisories and patch information. Affected products include: Python Urllib3.