A flaw was found in the libxml2 library. This uncontrolled resource consumption vulnerability occurs when processing XML catalogs that contain repeated elements pointing to the same downstream catalog. A remote attacker can exploit this by supplying crafted catalogs, causing the parser to redundantly traverse catalog chains. This leads to excessive CPU consumption and degrades application availability, resulting in a denial-of-service condition.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libxml2 | Ubuntu | esm-infra-legacy/trusty | * |
| Libxml2 | Ubuntu | esm-infra/bionic | * |
| Libxml2 | Ubuntu | esm-infra/focal | * |
| Libxml2 | Ubuntu | esm-infra/xenial | * |
| Libxml2 | Ubuntu | jammy | * |
| Libxml2 | Ubuntu | noble | * |
| Libxml2 | Ubuntu | questing | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.