CVE-2025-48956

7.5

vLLM Project · vLLM

A denial of service vulnerability in vLLM allows unauthenticated remote attackers to cause server memory exhaustion and crashes by sending an HTTP GET request with an excessively large header.

Executive summary

An unauthenticated denial of service vulnerability in vLLM can be exploited by remote attackers to crash inference engines via memory exhaustion.

Vulnerability

This is a resource consumption vulnerability (CWE-400) where the application fails to properly limit the size of incoming HTTP headers. An unauthenticated remote attacker can trigger this vulnerability by sending a single malicious GET request, forcing the server to exhaust its available memory.

Business impact

Successful exploitation of this vulnerability results in service disruption, as the inference engine will likely crash or become unresponsive. Given the CVSS score of 7.5, this high-severity flaw poses a significant risk to the availability of AI-driven applications and services that rely on vLLM for model serving, potentially leading to operational downtime and business process interruptions.

Remediation

Immediate Action: Update the vLLM package to version 0.10.1.1 or later immediately to incorporate the necessary resource handling fixes.

Proactive Monitoring: Monitor server resource utilization logs for unusual memory spikes or frequent service restarts that may indicate attempted exploitation.

Compensating Controls: Implement a Web Application Firewall (WAF) or an API gateway in front of the vLLM service to enforce strict limits on incoming request header sizes and reject oversized requests.

Exploitation status

Public Exploit Available: Unknown.

Analyst recommendation

This vulnerability represents a critical threat to service availability for organizations deploying vLLM. IT and security teams must prioritize the update to version 0.10.1.1 as soon as possible. In environments where immediate patching is not feasible, deploying edge-level request filtering is essential to prevent potential service outages caused by malicious actors.

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