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CursorApplication · Anysphere

CVE-2025-54135

CRITICAL · 9.8 CVSS v3.1 Published 2025-08-05
Fix available
A fix is available. Upgrade to 1.3.9 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Cursor is a code editor built for programming with AI. Cursor allows writing in-workspace files with no user approval in versions below 1.3.9, If the file is a dotfile, editing it requires approval but creating a new one doesn't. Hence, if sensitive MCP files, such as the .cursor/mcp.json file don't already exist in the workspace, an attacker can chain a indirect prompt injection vulnerability to hijack the context to write to the settings file and trigger RCE on the victim without user approval. This is fixed in version 1.3.9.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Cursor versions below 1.3.9 allow unauthenticated file creation in workspaces. While editing dotfiles requires approval, creating new dotfiles (like .cursor/mcp.json) does not. An attacker can exploit this via indirect prompt injection to write malicious settings and achieve RCE without user interaction.

MitigationUpgrade Cursor to version 1.3.9 or later to patch the unauthenticated file creation vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
CursorApplication
Affected:< 1.3.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Cursor version
    Open Cursor, go to Cursor Settings (or Help > About), and note the version number displayed. Alternatively, check the application's Info.plist or app metadata.
    Affected if The version is below 1.3.9 (e.g., 1.3.8, 1.3.7, etc.)
  2. Verify MCP configuration file presence
    Inspect the .cursor/mcp.json file in the user's home directory or within project directories. This file is located at ~/.cursor/mcp.json or in the workspace root as .cursor/mcp.json.
    Affected if The .cursor/mcp.json file exists in the environment
  3. Inspect MCP server configurations
    Open and review the contents of any .cursor/mcp.json file found. Look for defined MCP servers, particularly those with external or network-based endpoints.
    Affected if The MCP configuration contains server definitions, especially remote/network-based servers that could accept injected prompts
  4. Assess network exposure
    Determine if the system has outbound network access or if the Cursor installation interacts with remote MCP servers or external services.
    Affected if Network connectivity is available and MCP servers are configured to connect to external endpoints

The environment is affected if the installed Cursor version is below 1.3.9 and an MCP configuration file (.cursor/mcp.json) exists with server definitions that could be exploited through indirect prompt injection.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.3.9 or later
Fixed in 1.3.9
Interim mitigation

Upgrade Cursor to version 1.3.9 or later to patch the unauthenticated file creation vulnerability.

Recommended fix High confidence

Cursor 1.3.9 or latest stable release

  1. Upgrade Cursor to version 1.3.9 or later to remediate the vulnerability
  2. Verify the upgrade was successful by checking the Cursor version in the application settings or about menu
  3. Ensure no untrusted or malicious MCP configurations were added to .cursor/mcp.json during the vulnerable period
  4. If you suspect compromise, review and audit any recently created or modified configuration files in the .cursor directory

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Cursor Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-54135 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data