Description
An issue was discovered in Python before 3.11.1. An unnecessary quadratic algorithm exists in one path when processing some inputs to the IDNA (RFC 3490) decoder, such that a crafted, unreasonably long name being presented to the decoder could lead to a CPU denial of service. Hostnames are often supplied by remote servers that could be controlled by a malicious actor; in such a scenario, they could trigger excessive CPU consumption on the client attempting to make use of an attacker-supplied supposed hostname. For example, the attack payload could be placed in the Location header of an HTTP response with status code 302. A fix is planned in 3.11.1, 3.10.9, 3.9.16, 3.8.16, and 3.7.16.
CVSS Metrics
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack Vector
- network
- Complexity
- low
- Privileges
- none
- User Action
- none
- Scope
- unchanged
- Confidentiality
- none
- Integrity
- none
- Availability
- high
- Weaknesses
- CWE-407CWE-407
Metadata
- Primary Vendor
- PYTHON
- Published
- 11/9/2022
- Last Modified
- 11/3/2025
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
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