# 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.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 May 2025
- **Updated:** 30 May 2025
- **Also known as:** GHSA-w6q7-j642-7c25, PYSEC-2025-50

## 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 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2025-48887?

3 open source packages ship an affected version, including vllm. It affects 1 product.


| Package | Ecosystem | 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: Vllm Vllm.

## How do I fix CVE-2025-48887?

Upgrade vllm to 0.9.0 or later.

## 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](https://insights.sbomify.com/CVE-2025-32444/): vLLM Vulnerable to Remote Code Execution via Mooncake Integration (critical 10.0)
- [CVE-2026-22778](https://insights.sbomify.com/CVE-2026-22778/): vLLM leaks a heap address when PIL throws an error (critical 9.8)
- [CVE-2025-47277](https://insights.sbomify.com/CVE-2025-47277/): vLLM Allows Remote Code Execution via PyNcclPipe Communication Service (critical 9.8)
- [CVE-2024-11041](https://insights.sbomify.com/CVE-2024-11041/): Remote Code Execution in vllm-project/vllm (critical 9.8)
- [CVE-2026-48746](https://insights.sbomify.com/CVE-2026-48746/): vLLM: OpenAI auth bypass (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-48887 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-48887 exists.

Affected packages and fixed versions:
- vllm (PyPI): affected from 0.6.4; fixed in 0.9.0
- vllm (PyPI): affected from 0.6.4; fixed in 0.9.0
- vllm (PyPI): affected from 0.6.4; fixed in 0.9.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-48887/ (Markdown: https://insights.sbomify.com/CVE-2025-48887/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-48887
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-48887
- OSV: https://osv.dev/vulnerability/CVE-2025-48887

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-48887/
Summaries are generated and may contain mistakes; the official description above is the record.