CVE search · CVE-2020-7212
CVE-2020-7212
high 7.5
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).
Details
- Status
- Modified
- Published
- Last changed
- Source
- cve@mitre.org
- Weakness
- CWE-400
Severity
| Version | Score | Vector | Source |
|---|---|---|---|
| CVSS 3.1 | high 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
nvd@nist.govPrimary |
| CVSS 2.0 | high 7.8 | AV:N/AC:L/Au:N/C:N/I:N/A:C |
nvd@nist.govPrimary |
Affected products
Vendor and product from the NVD’s CPE applicability statements. Versions and conditions are on the NVD’s page.
- python · urllib3
References
- https://github.com/urllib3/urllib3/blob/master/CHANGES.rstRelease NotesThird Party Advisory
- https://github.com/urllib3/urllib3/commit/a74c9cfbaed9f811e7563cfc3dce894928e0221aPatchThird 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/a74c9cfbaed9f811e7563cfc3dce894928e0221aPatchThird Party Advisory
- https://pypi.org/project/urllib3/1.25.8/Release NotesVendor Advisory