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.
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Python | Python | * | 3.7.15 (including) |
| Python | Python | 3.8.0 (including) | 3.8.15 (including) |
| Python | Python | 3.9.0 (including) | 3.9.15 (including) |
| Python | Python | 3.10.0 (including) | 3.10.8 (including) |
| Python | Python | 3.11.0 (including) | 3.11.0 (including) |
| Python | Python | 3.11.0-alpha1 (including) | 3.11.0-alpha1 (including) |
| Python | Python | 3.11.0-alpha2 (including) | 3.11.0-alpha2 (including) |
| Python | Python | 3.11.0-alpha3 (including) | 3.11.0-alpha3 (including) |
| Python | Python | 3.11.0-alpha4 (including) | 3.11.0-alpha4 (including) |
| Python | Python | 3.11.0-alpha5 (including) | 3.11.0-alpha5 (including) |
| Python | Python | 3.11.0-alpha6 (including) | 3.11.0-alpha6 (including) |
| Python | Python | 3.11.0-alpha7 (including) | 3.11.0-alpha7 (including) |
| Python | Python | 3.11.0-beta1 (including) | 3.11.0-beta1 (including) |
| Python | Python | 3.11.0-beta2 (including) | 3.11.0-beta2 (including) |
| Python | Python | 3.11.0-beta3 (including) | 3.11.0-beta3 (including) |
| Python | Python | 3.11.0-beta4 (including) | 3.11.0-beta4 (including) |
| Python | Python | 3.11.0-beta5 (including) | 3.11.0-beta5 (including) |
| Python | Python | 3.11.0-rc1 (including) | 3.11.0-rc1 (including) |
| Python | Python | 3.11.0-rc2 (including) | 3.11.0-rc2 (including) |