CVE-2025-48956

Description

### Summary A Denial of Service (DoS) vulnerability can be triggered by sending a single HTTP GET request with an extremely large header to an HTTP endpoint. This results in server memory exhaustion, potentially leading to a crash or unresponsiveness. The attack does not require authentication, making it exploitable by any remote user. ### Details The vulnerability leverages the abuse of HTTP headers. By setting a header such as `X-Forwarded-For` to a very large value like `("A" * 5_800_000_000)`, the server's HTTP parser or application logic may attempt to load the entire request into memory, overwhelming system resources. ### Impact _What kind of vulnerability is it? Who is impacted?_ Type of vulnerability: Denial of Service (DoS) ### Resolution Upgrade to a version of vLLM that includes appropriate HTTP limits by deafult, or use a proxy in front of vLLM which provides protection against this issue.

How to fix CVE-2025-48956

To remediate CVE-2025-48956, upgrade the affected package to a fixed version below.

• —upgrade to 0.10.1.1 or later

Is CVE-2025-48956 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• >= 0.1.0, < 0.10.1.1

CVSS scores

References (5)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2025-48956
• PATCHgithub.com/vllm-project/vllm
• WEBgithub.com/vllm-project/vllm/commit/d8b736f913a59117803d6701521d2e4861701944
• WEBgithub.com/vllm-project/vllm/pull/23267