Publish GHSA-vc6m-hm49-g9qg

advisories/github-reviewed/2025/04/GHSA-vc6m-hm49-g9qg/GHSA-vc6m-hm49-g9qg.json

@@ -1,9 +1,11 @@
 {
   "schema_version": "1.4.0",
   "id": "GHSA-vc6m-hm49-g9qg",
-  "modified": "2025-04-29T16:43:10Z",
+  "modified": "2025-04-29T20:38:26Z",
   "published": "2025-04-29T16:43:10Z",
-  "aliases": [],
+  "aliases": [
+    "CVE-2025-46560"
+  ],
   "summary": "phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service",
   "details": "### Summary\nA critical performance vulnerability has been identified in the input preprocessing logic of the multimodal tokenizer. The code dynamically replaces placeholder tokens (e.g., <|audio_*|>, <|image_*|>) with repeated tokens based on precomputed lengths. Due to ​​inefficient list concatenation operations​​, the algorithm exhibits ​​quadratic time complexity (O(n²))​​, allowing malicious actors to trigger resource exhaustion via specially crafted inputs.\n\n### Details\n​​Affected Component​​: input_processor_for_phi4mm function.\nhttps://github.com/vllm-project/vllm/blob/8cac35ba435906fb7eb07e44fe1a8c26e8744f4e/vllm/model_executor/models/phi4mm.py#L1182-L1197\n\nThe code modifies the input_ids list in-place using input_ids = input_ids[:i] + tokens + input_ids[i+1:]. Each concatenation operation copies the entire list, leading to O(n) operations per replacement. For k placeholders expanding to m tokens, total time becomes O(kmn), approximating O(n²) in worst-case scenarios.\n\n### PoC\nTest data demonstrates exponential time growth:\n```python\ntest_cases = [100, 200, 400, 800, 1600, 3200, 6400]\nrun_times = [0.002, 0.007, 0.028, 0.136, 0.616, 2.707, 11.854]  # seconds\n```\nDoubling input size increases runtime by ~4x (consistent with O(n²)).\n\n### Impact\n​​Denial-of-Service (DoS):​​ An attacker could submit inputs with many placeholders (e.g., 10,000 <|audio_1|> tokens), causing CPU/memory exhaustion.\nExample: 10,000 placeholders → ~100 million operations.\n\n\n### Remediation Recommendations​\nPrecompute all placeholder positions and expansion lengths upfront.\nReplace dynamic list concatenation with a single preallocated array.\n```python\n# Pseudocode for O(n) solution\nnew_input_ids = []\nfor token in input_ids:\n    if token is placeholder:\n        new_input_ids.extend([token] * precomputed_length)\n    else:\n        new_input_ids.append(token)\n```",
   "severity": [