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TI-2025-33978 Aliases CVE-2025-54135

Cursor Agent is vulnerable to prompt injection via MCP Special Files

Priority MEDIUM 47CWE-78Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-78.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0213 82nd percentileScored 2026-11-07
Fix Fixed cursor (cursor): 1.3.9

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
cursorcursorbefore 1.3.91.3.9Patch availableCNA
  • cursor Vendorcursor Affected before 1.3.9 Fixed in 1.3.9 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:anysphere:cursor:*:*:*:*:*:*:*:*before 1.3.9Vulnerablecursor
  • cpe:2.3:a:anysphere:cursor:*:*:*:*:*:*:*:* Versions before 1.3.9 Vulnerable ·cursor

Remediation

  • Fix · CNA cursor (cursor) Fixed in 1.3.9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-54135

References

Advisory 1

  • TI-2026-45043 Cursor for Windows 3.2.16 RCE via Malicious git.exe in Workspace CVSS 4.0HIGH 8.7
  • TI-2025-33979 Cursor's Modification of MCP Server Definitions Bypasses Manual Re-approvals CVSS 3.1HIGH 8.8
  • TI-2026-37271 Cursor Desktop sandbox escape via symlink and failed path canonicalization CVSS 4.0CRITICAL 9.3
  • TI-2026-37270 Cursor Desktop sandbox escape via agent-controlled working directory CVSS 4.0CRITICAL 9.3
  • TI-2025-38037 Cursor CLI's Cursor Agent MCP OAuth2 Communication is Vulnerable to Remote Code Execution CVSS 3.1HIGH 8.8
  • TI-2026-21238 Cursor sandbox escape via Git hooks CVSS 3.1CRITICAL 9.9
See all 21 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences