CVE-2024-8939

Public on

Last Modified: UTC

Description

A vulnerability was found in the ilab model serve component, where improper handling of the best_of parameter in the vllm JSON web API can lead to a Denial of Service (DoS). The API used for LLM-based sentence or chat completion accepts a best_of parameter to return the best completion from several options. When this parameter is set to a large value, the API does not handle timeouts or resource exhaustion properly, allowing an attacker to cause a DoS by consuming excessive system resources. This leads to the API becoming unresponsive, preventing legitimate users from accessing the service.

A vulnerability was found in the ilab model serve component, where improper handling of the best_of parameter in the vllm JSON web API can lead to a Denial of Service (DoS). The API used for LLM-based sentence or chat completion accepts a best_of parameter to return the best completion from several options. When this parameter is set to a large value, the API does not handle timeouts or resource exhaustion properly, allowing an attacker to cause a DoS by consuming excessive system resources. This leads to the API becoming unresponsive, preventing legitimate users from accessing the service.

Statement

The improper timeout handling vulnerability in the ilab model serve component is classified as a moderate severity issue rather than an important one because its impact is contingent upon the exposure of the API beyond localhost. While the vulnerability can lead to a Denial of Service (DoS) by causing excessive processing times for requests with a high `best_of` parameter, its effect is primarily localized to the server environment where the API is accessible externally. This means that if the API is not exposed to the public or is adequately secured, the risk of exploitation is significantly reduced. Additionally, the issue does not involve unauthorized data access or compromise of sensitive information, which limits its overall impact.

The improper timeout handling vulnerability in the ilab model serve component is classified as a moderate severity issue rather than an important one because its impact is contingent upon the exposure of the API beyond localhost. While the vulnerability can lead to a Denial of Service (DoS) by causing excessive processing times for requests with a high best_of parameter, its effect is primarily localized to the server environment where the API is accessible externally. This means that if the API is not exposed to the public or is adequately secured, the risk of exploitation is significantly reduced. Additionally, the issue does not involve unauthorized data access or compromise of sensitive information, which limits its overall impact.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Additional information

  • Bugzilla 2312782: vllm: Denials of Service in vllm JSON web API
  • CWE-400: Uncontrolled Resource Consumption
  • FAQ: Frequently asked questions about CVE-2024-8939

Common Vulnerability Scoring System (CVSS) Score Details

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 HatNVD

CVSS v3 Base Score

6.2

N/A

Attack Vector

Local

N/A

Attack Complexity

Low

N/A

Privileges Required

None

N/A

User Interaction

None

N/A

Scope

Unchanged

N/A

Confidentiality Impact

None

N/A

Integrity Impact

None

N/A

Availability Impact

High

N/A

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Understanding the Weakness (CWE)

CWE-400

Availability

Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)

The most common result of resource exhaustion is denial of service. The product may slow down, crash due to unhandled errors, or lock out legitimate users.

Access Control,Other

Technical Impact: Bypass Protection Mechanism; Other

In some cases it may be possible to force the product to "fail open" in the event of resource exhaustion. The state of the product -- and possibly the security functionality - may then be compromised.

Acknowledgements

Red Hat would like to thank Thibault Guittet for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

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