CVE-2025-54135Network attack vector

Code execution via unauthorized MCP configuration creation

Published Aug 5, 2025 · Updated Aug 5, 2025

Prompt injection in Cursor before 1.3.9 allows attackers to execute arbitrary code through an unauthorized MCP configuration. Agent permits creation of a new dotfile without approval, so injected instructions can create .cursor/mcp.json and register attacker-chosen MCP commands. The chain requires that sensitive file to be absent and malicious instructions to enter Agent context; registered commands then run without approval.

CVSS severity8.6
High
EPSS probability1.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prompt injection in Cursor before 1.3.9 allows attackers to execute arbitrary code through an unauthorized MCP configuration. Agent permits creation of a new dotfile without approval, so injected instructions can create .cursor/mcp.json and register attacker-chosen MCP commands. The chain requires that sensitive file to be absent and malicious instructions to enter Agent context; registered commands then run without approval.

The record

CVE
CVE-2025-54135
Published
Aug 5, 2025
Updated
Aug 5, 2025
Vendor
Anysphere
Product
Cursor
Classifications
CWE-829, CWE-78, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=< 1.3.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Anysphere · Cursorversion=< 1.3.9

Published CVSS scores

8.6GitHubCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-829Inclusion of Functionality from Untrusted Control Sphere
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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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