CVE-2025-48887Public exploitNetwork attack vector

Authenticated service interruption via catastrophic regex backtracking

Published May 30, 2025 · Updated May 30, 2025

Regular expression denial of service in vLLM allows remote authenticated users to freeze or crash the API service with crafted tool-call output. In pythonic_tool_parser.py, the parser applies a nested, repetition-heavy expression to model-generated tool-call text, causing exponential backtracking. Reachability requires prompt access and automatic tool choice with the pythonic parser; crafted output can monopolize CPU, retain GPU cache, and interrupt service.

CVSS severity6.5
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in vLLM allows remote authenticated users to freeze or crash the API service with crafted tool-call output. In pythonic_tool_parser.py, the parser applies a nested, repetition-heavy expression to model-generated tool-call text, causing exponential backtracking. Reachability requires prompt access and automatic tool choice with the pythonic parser; crafted output can monopolize CPU, retain GPU cache, and interrupt service.

The record

CVE
CVE-2025-48887
Published
May 30, 2025
Updated
May 30, 2025
Vendor
vLLM Project
Product
vLLM
Classifications
CWE-1333, CAPEC-492, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 30, 2025CVE publishedPublication date reported by the CVE source.
  2. May 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.6.4, < 0.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

vLLM Project · vLLMversion=>= 0.6.4, < 0.9.0

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
CAPEC-492Regular Expression Exponential Blowup
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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