From 3b78bcb231cb9509d9105898ad513be6b1f86400 Mon Sep 17 00:00:00 2001
From: "advisory-database[bot]"
 <45398580+advisory-database[bot]@users.noreply.github.com>
Date: Tue, 15 Apr 2025 21:24:23 +0000
Subject: [PATCH] Publish GHSA-hf3c-wxg2-49q9

---
 .../GHSA-hf3c-wxg2-49q9.json                  | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 advisories/github-reviewed/2025/04/GHSA-hf3c-wxg2-49q9/GHSA-hf3c-wxg2-49q9.json

diff --git a/advisories/github-reviewed/2025/04/GHSA-hf3c-wxg2-49q9/GHSA-hf3c-wxg2-49q9.json b/advisories/github-reviewed/2025/04/GHSA-hf3c-wxg2-49q9/GHSA-hf3c-wxg2-49q9.json
new file mode 100644
index 00000000000..eaf798d3c91
--- /dev/null
+++ b/advisories/github-reviewed/2025/04/GHSA-hf3c-wxg2-49q9/GHSA-hf3c-wxg2-49q9.json
@@ -0,0 +1,68 @@
+{
+  "schema_version": "1.4.0",
+  "id": "GHSA-hf3c-wxg2-49q9",
+  "modified": "2025-04-15T21:21:04Z",
+  "published": "2025-04-15T21:21:04Z",
+  "aliases": [],
+  "summary": "vLLM vulnerable to Denial of Service by abusing xgrammar cache",
+  "details": "### Impact\n\nThis report is to highlight a vulnerability in XGrammar, a library used by the structured output feature in vLLM. The XGrammar advisory is here: https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-389x-67px-mjg3\n\nThe [xgrammar](https://xgrammar.mlc.ai/docs/) library is the default backend used by vLLM to support structured output (a.k.a. guided decoding). Xgrammar provides a required, built-in cache for its compiled grammars stored in RAM. xgrammar is available by default through the OpenAI compatible API server with both the V0 and V1 engines.\n\nA malicious user can send a stream of very short decoding requests with unique schemas, resulting in an addition to the cache for each request. This can result in a Denial of Service by consuming all of the system's RAM.\n\nNote that even if vLLM was configured to use a different backend by default, it is still possible to choose xgrammar on a per-request basis using the `guided_decoding_backend` key of the `extra_body` field of the request with the V0 engine. This per-request choice is not available when using the V1 engine. \n### Patches\n\n* https://github.com/vllm-project/vllm/pull/16283\n\n### Workarounds\n\nThere is no way to workaround this issue in existing versions of vLLM other than preventing untrusted access to the OpenAI compatible API server.\n\n### References\n\n* https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-389x-67px-mjg3",
+  "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": "0.6.5"
+            },
+            {
+              "fixed": "0.8.4"
+            }
+          ]
+        }
+      ]
+    }
+  ],
+  "references": [
+    {
+      "type": "WEB",
+      "url": "https://github.com/mlc-ai/xgrammar/security/advisories/GHSA-389x-67px-mjg3"
+    },
+    {
+      "type": "WEB",
+      "url": "https://github.com/vllm-project/vllm/security/advisories/GHSA-hf3c-wxg2-49q9"
+    },
+    {
+      "type": "WEB",
+      "url": "https://github.com/vllm-project/vllm/pull/16283"
+    },
+    {
+      "type": "WEB",
+      "url": "https://github.com/vllm-project/vllm/commit/cb84e45ac75b42ba6795145923e8eb323bb825ad"
+    },
+    {
+      "type": "PACKAGE",
+      "url": "https://github.com/vllm-project/vllm"
+    }
+  ],
+  "database_specific": {
+    "cwe_ids": [
+      "CWE-1395",
+      "CWE-770"
+    ],
+    "severity": "MODERATE",
+    "github_reviewed": true,
+    "github_reviewed_at": "2025-04-15T21:21:04Z",
+    "nvd_published_at": null
+  }
+}
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