CVE-2025-48943

vLLM allows clients to crash the openai server with invalid regex

Description

vLLM is an inference and serving engine for large language models (LLMs). Version 0.8.0 up to but excluding 0.9.0 have a Denial of Service (ReDoS) that causes the vLLM server to crash if an invalid regex was provided while using structured output. This vulnerability is similar to GHSA-6qc9-v4r8-22xg/CVE-2025-48942, but for regex instead of a JSON schema. Version 0.9.0 fixes the issue.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.04%
Vendor Advisory github.com
Affected: vllm-project vllm
Published at:
Updated at:

References

Link Tags
https://github.com/vllm-project/vllm/security/advisories/GHSA-9hcf-v7m4-6m2j vendor advisory
https://github.com/vllm-project/vllm/issues/17313 issue tracking
https://github.com/vllm-project/vllm/pull/17623 issue tracking patch
https://github.com/vllm-project/vllm/commit/08bf7840780980c7568c573c70a6a8db94fd45ff patch

Frequently Asked Questions

What is the severity of CVE-2025-48943?
CVE-2025-48943 has been scored as a medium severity vulnerability.
How to fix CVE-2025-48943?
To fix CVE-2025-48943, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-48943 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-48943 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-48943?
CVE-2025-48943 affects vllm-project vllm.
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