NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).
Weakness
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.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Unbound | Nlnetlabs | * | 1.25.1 (excluding) |
| Unbound | Ubuntu | devel | * |
| Unbound | Ubuntu | esm-infra/bionic | * |
| Unbound | Ubuntu | esm-infra/focal | * |
| Unbound | Ubuntu | esm-infra/xenial | * |
| Unbound | Ubuntu | jammy | * |
| Unbound | Ubuntu | noble | * |
| Unbound | Ubuntu | questing | * |
| Unbound | Ubuntu | resolute | * |