CVE-2025-48956: Vllm Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-rxc4-3w6r-4v47
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CVSS 7.5
CWE-400
Published
Advisory Summary

CVE-2025-48956 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Vllm libraries in the PyPI ecosystem. The issue involves vllm api endpoints vulnerable to denial of service attacks. Remediation is available by upgrading affected packages to version 0.10.1.1.

CVE-2025-48956 at a Glance

CVE Identifier CVE-2025-48956
GHSA Identifier GHSA-rxc4-3w6r-4v47
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Vllm
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2025-48956

To remediate this vulnerability, upgrade all affected Vllm dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

vllm fixed: 0.10.1.1 
pip install vllm>=0.10.1.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show vllm

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-48956, inspect your installed packages using pip:

pip show vllm

Analyze the terminal output to locate any version of Vllm in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.10.1.1), your application is affected.

Note: The pip show vllm command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Vllm, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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.

CVE-2025-48956 Affected Vllm Versions

1 component(s)
Fixed Versions:
0.10.1.1
Product / Package Ecosystem Affected Versions Fixed Version
vllm
pypi/vllm
PyPI
≥ 0.1.0
< 0.10.1.1
0.10.1.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vllm-project/vllm/security/advisories/GHSA-rxc4-3w6r-4v47
NVD — CVE-2025-48956 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-48956
Vllm Source Repository REPOSITORY
https://github.com/vllm-project/vllm/pull/23267
Security Fix Commit FIX COMMIT
https://github.com/vllm-project/vllm/commit/d8b736f913a59117803d6701521d2e4861701944
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-rxc4-3w6r-4v47
Vllm Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2026-2021.yaml
Vllm Source Repository REPOSITORY
https://github.com/vllm-project/vllm
pypi.org/project/vllm WEB
https://pypi.org/project/vllm

Frequently Asked Questions

What is CVE-2025-48956?
CVE-2025-48956 is a security vulnerability in Vllm involving vllm API endpoints vulnerable to Denial of Service Attacks under CWE-400: Uncontrolled Resource Consumption.
Which Vllm versions are affected?
Affected versions include releases prior to 0.10.1.1 across affected packages: vllm.
What version fixes CVE-2025-48956?
Upgrading to 0.10.1.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is vllm affected?
Yes, vllm is affected in releases prior to 0.10.1.1. Upgrade your dependency to 0.10.1.1 or later.
What is the CVSS score of CVE-2025-48956?
CVE-2025-48956 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2025-48956?
CVE-2025-48956 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check PyPI dependencies for CVE-2025-48956?
Run the dependency tree command: 'pip show vllm'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rxc4-3w6r-4v47",
  "modified" : "2026-07-17T16:14:41Z",
  "published" : "2025-08-21T14:24:16Z",
  "aliases" : [ "CVE-2025-48956" ],
  "summary" : "vllm API endpoints vulnerable to Denial of Service Attacks",
  "details" : "### Summary\nA 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.\n\n### Details\nThe 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.\n\n### Impact\n_What kind of vulnerability is it? Who is impacted?_\nType of vulnerability: Denial of Service (DoS)\n\n### Resolution\nUpgrade 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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "vllm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.1.0"
      }, {
        "fixed" : "0.10.1.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/security/advisories/GHSA-rxc4-3w6r-4v47"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-48956"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/pull/23267"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/commit/d8b736f913a59117803d6701521d2e4861701944"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-rxc4-3w6r-4v47"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2026-2021.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vllm-project/vllm"
  }, {
    "type" : "WEB",
    "url" : "https://pypi.org/project/vllm"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-08-21T14:24:16Z",
    "nvd_published_at" : "2025-08-21T15:15:32Z"
  }
}