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 |
|---|---|---|---|---|---|---|---|---|
| Debian 13 | python | 3.9 | 7.5 | HIGH | Not Vulnerable | 2025-12-05 14:56:34 | ||
| Debian 13 | python | 3.6 | 7.5 | HIGH | Released | CLSA-2025:1759247594 | 2025-10-01 01:12:45 | |
| Debian 13 | python | 2.7 | 7.5 | HIGH | Released | CLSA-2025:1760114590 | 2025-10-10 22:15:46 | |
| Debian 13 | python | 3.8 | 7.5 | HIGH | Not Vulnerable | 2025-11-21 15:04:05 | ||
| Debian 13 | python | 3.7 | 7.5 | HIGH | Not Vulnerable | 2025-11-21 15:04:06 | ||
| EL 10 | python | 2.7 | 7.5 | HIGH | Already Fixed | 2025-10-01 01:11:25 | ||
| EL 10 | python | 3.6 | 7.5 | HIGH | Already Fixed | 2025-10-29 18:42:40 | ||
| EL 7 | python | 2.7 | 7.5 | HIGH | Released | CLSA-2025:1753804481 | 2025-07-30 01:44:50 | |
| EL 7 | python | 3.6 | 7.5 | HIGH | Released | CLSA-2025:1748350001 | 2025-05-28 00:19:26 | |
| EL 8 | python | 2.7 | 7.5 | HIGH | Released | CLSA-2025:1753804756 | 2025-07-30 01:44:49 |