Updated: 2025-11-10 00:12:25.998685
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.
| Links | NIST | CIRCL | RHEL | Ubuntu |
| Severity | Score | |
|---|---|---|
| CVSS Version 2.x | 0.0 | |
| CVSS Version 3.x | HIGH | 7.5 |
| OS name | Project name | Version | Score | Severity | Status | Errata | Last updated | Statement |
|---|---|---|---|---|---|---|---|---|
| Alpine Linux 3.22 | python | 3.6 | 7.5 | HIGH | Released | CLSA-2026:1769524909 | 2026-01-27 16:42:28 | |
| Debian 10 | python | 3.6 | 7.5 | HIGH | Released | CLSA-2025:1759247273 | 2025-10-01 01:26:36 | |
| Debian 10 | python | 2.7 | 7.5 | HIGH | Released | CLSA-2025:1760024436 | 2025-10-10 00:47:36 | |
| Debian 11 | python | 2.7 | 7.5 | HIGH | Released | CLSA-2025:1760093456 | 2025-10-10 11:24:35 | |
| Debian 11 | python | 3.6 | 7.5 | HIGH | Released | CLSA-2025:1759247378 | 2025-10-01 01:26:35 | |
| Debian 12 | python | 3.9 | 7.5 | HIGH | Not Vulnerable | 2025-12-05 14:56:34 | ||
| Debian 12 | python | 3.7 | 7.5 | HIGH | Not Vulnerable | 2025-11-21 15:04:04 | ||
| Debian 12 | python | 3.6 | 7.5 | HIGH | Released | CLSA-2025:1759247489 | 2025-10-01 01:26:34 | |
| Debian 12 | python | 2.7 | 7.5 | HIGH | Released | CLSA-2025:1760093575 | 2025-10-10 11:24:33 | |
| Debian 12 | python | 3.8 | 7.5 | HIGH | Not Vulnerable | 2025-11-21 15:04:03 |