CVE-2024-1931
Description
A vulnerability was found in Unbound. The issue arises due to a flaw in the handling of Extended DNS Error (EDE) records when the 'ede: yes' option is enabled, a non-default configuration. Specifically, an unchecked condition in the code can trigger an infinite loop when attempting to trim the text fields of EDE records to fit within the client's buffer size. This vulnerability could potentially lead to denial of service (DoS) as the infinite loop consumes system resources, impacting the availability of the Unbound DNS resolver.
Statement
The vulnerability present in Unbound, while posing a risk of denial of service, is assessed as having a Moderate severity level from a technical perspective. The severity is primarily attributed to the potential for exploitation under specific conditions, namely when the 'ede: yes' option is enabled, which is not the default configuration. Additionally, the vulnerability manifests in a limited scenario where responses containing Extended DNS Error (EDE) records exceed the client's buffer size. While the issue can result in an infinite loop and consequent denial of service, its impact is constrained to situations where these specific conditions align.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.
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