CVE-2025-48943: Vllm VLLM Allows Clients To Crash Vulnerability

MODERATE
Advisory Identifier: GHSA-9hcf-v7m4-6m2j
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CVSS 6.5
CWE-248
Published
Advisory Summary

CVE-2025-48943 is a MODERATE (CVSS 6.5) vllm allows clients to crash vulnerability (CWE-248: Uncaught Exception) affecting Vllm libraries in the PyPI ecosystem. The issue involves vllm allows clients to crash the openai server with invalid regex. Remediation is available by upgrading affected packages to version 0.9.0.

CVE-2025-48943 at a Glance

CVE Identifier CVE-2025-48943
GHSA Identifier GHSA-9hcf-v7m4-6m2j
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-248: Uncaught Exception
Affected Product Vllm
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.5

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
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-2025-48943

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: 0.9.0 
pip install vllm>=0.9.0
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-2025-48943, 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 0.9.0), 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-248: Uncaught Exception, where an exception is thrown from a function, but it is not caught. 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

### Impact A denial of service bug caused the vLLM server to crash if an invalid regex was provided while using structured output. This vulnerability is similar to [GHSA-6qc9-v4r8-22xg](https://github.com/vllm-project/vllm/security/advisories/GHSA-6qc9-v4r8-22xg), but for regex instead of a JSON schema. Issue with more details: https://github.com/vllm-project/vllm/issues/17313 ### Patches * https://github.com/vllm-project/vllm/pull/17623

CVE-2025-48943 Affected Vllm Versions

1 component(s)
Fixed Versions:
0.9.0
Product / Package Ecosystem Affected Versions Fixed Version
vllm
pypi/vllm
PyPI
≥ 0.8.0
< 0.9.0
0.9.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vllm-project/vllm/security/advisories/GHSA-9hcf-v7m4-6m2j
NVD — CVE-2025-48943 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-48943
Vllm Source Repository REPOSITORY
https://github.com/vllm-project/vllm/issues/17313
Vllm Source Repository REPOSITORY
https://github.com/vllm-project/vllm/pull/17623
Security Fix Commit FIX COMMIT
https://github.com/vllm-project/vllm/commit/08bf7840780980c7568c573c70a6a8db94fd45ff
Vllm Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2025-55.yaml
Vllm Source Repository REPOSITORY
https://github.com/vllm-project/vllm

Frequently Asked Questions

What is CVE-2025-48943?
CVE-2025-48943 is a security vulnerability in Vllm involving vLLM allows clients to crash the openai server with invalid regex under CWE-248: Uncaught Exception.
Which Vllm versions are affected?
Affected versions include releases prior to 0.9.0 across affected packages: vllm.
What version fixes CVE-2025-48943?
Upgrading to 0.9.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is vllm affected?
Yes, vllm is affected in releases prior to 0.9.0. Upgrade your dependency to 0.9.0 or later.
What is the CVSS score of CVE-2025-48943?
CVE-2025-48943 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2025-48943?
CVE-2025-48943 is classified under CWE-248: Uncaught Exception (An exception is thrown from a function, but it is not caught.).
How can I check PyPI dependencies for CVE-2025-48943?
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-9hcf-v7m4-6m2j",
  "modified" : "2025-06-27T21:07:04Z",
  "published" : "2025-05-28T19:42:12Z",
  "aliases" : [ "CVE-2025-48943" ],
  "summary" : "vLLM allows clients to crash the openai server with invalid regex",
  "details" : "### Impact\n\nA denial of service bug caused the vLLM server to crash if an invalid regex was provided while using structured output. This vulnerability is similar to [GHSA-6qc9-v4r8-22xg](https://github.com/vllm-project/vllm/security/advisories/GHSA-6qc9-v4r8-22xg), but for regex instead of a JSON schema.\n\nIssue with more details: https://github.com/vllm-project/vllm/issues/17313\n\n### Patches\n\n* https://github.com/vllm-project/vllm/pull/17623",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "vllm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.8.0"
      }, {
        "fixed" : "0.9.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/security/advisories/GHSA-9hcf-v7m4-6m2j"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-48943"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/issues/17313"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/pull/17623"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/commit/08bf7840780980c7568c573c70a6a8db94fd45ff"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2025-55.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vllm-project/vllm"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-248" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-05-28T19:42:12Z",
    "nvd_published_at" : "2025-05-30T19:15:30Z"
  }
}