CVE-2025-48887 vLLM has a Regular Expression Denial of Service (ReDoS, Exponential Complexity) Vulnerability in `pythonic_tool_parser.py`
An attacker can cause service unavailability in vLLM by exploiting a Regular Expression Denial of Service vulnerability in the tool parser.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-48887?
CVE-2025-48887 is a medium-severity denial of service vulnerability in Vllm Vllm, published on 30 May 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
vLLM, an inference and serving engine for large language models (LLMs), has a Regular Expression Denial of Service (ReDoS) vulnerability in the file `vllm/entrypoints/openai/tool_parsers/pythonic_tool_parser.py` of versions 0.6.4 up to but excluding 0.9.0. 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. The pattern contains multiple nested quantifiers, optional groups, and inner repetitions which make it vulnerable to catastrophic backtracking. Version 0.9.0 contains a patch for the issue.
Weakness: CWE-1333
Which versions are affected by CVE-2025-48887?
3 open source packages ship an affected version, including vllm. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vllm PyPI | From 0.6.4 | 0.9.0 |
vllm PyPI | From 0.6.4 | 0.9.0 |
vllm PyPI | From 0.6.4 | 0.9.0 |
Products include Vllm Vllm.
How do I fix CVE-2025-48887?
Upgrade vllm to 0.9.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-48887 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-48887 exists.
Other vulnerabilities in Vllm Vllm
- CVE-2025-32444 vLLM Vulnerable to Remote Code Execution via Mooncake Integration
- CVE-2026-22778 vLLM leaks a heap address when PIL throws an error
- CVE-2025-47277 vLLM Allows Remote Code Execution via PyNcclPipe Communication Service
- CVE-2024-11041 Remote Code Execution in vllm-project/vllm
- CVE-2026-48746 vLLM: OpenAI auth bypass
Sources
Also known as GHSA-w6q7-j642-7c25, PYSEC-2025-50.