---
title: "CVE-2025-54136: Cursor's Modification of MCP Server Definitions Bypasses Manual Re-approvals"
url: https://erroneo.us/security/cve/CVE-2025-54136/
description: "CVE-2025-54136 (cursor cursor): Cursor is a code editor built for programming with AI. In versions 1.2.4 and below, attackers can achieve remote and…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-08-01
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-54136"
kev: false
cvss: 7.2
epss: 0.28255
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-54136: Cursor's Modification of MCP Server Definitions Bypasses Manual Re-approvals

**Signal:** High exploit likelihood. EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 28.3% , percentile 98: FIRST’s model estimates a 28.3% chance of exploitation activity in the next 30 days, higher than 98% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Editorial verdict: Most can relax. Cursor CurXecute: Prompt Injection to RCE via mcp.json — Cursor auto-updates and both bugs were fixed by mid-2025; the lasting takeaway is to treat any agent that can write its own tool config as a code-execution path.

## What it is

Cursor is a code editor built for programming with AI. In versions 1.2.4 and below, attackers can achieve remote and persistent code execution by modifying an already trusted MCP configuration file inside a shared GitHub repository or editing the file locally on the target's machine. Once a collaborator accepts a harmless MCP, the attacker can silently swap it for a malicious command (e.g., calc.exe) without triggering any warning or re-prompt. If an attacker has write permissions on a user's active branches of a source repository that contains existing MCP servers the user has previously approved, or allows an attacker has arbitrary file-write locally, the attacker can achieve arbitrary code execution. This is fixed in version 1.3.

## Affected products (CVE record)

- cursor cursor: < 1.3

## Severity

- GitHub_M CVSS 3.1: 7.2 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 28.26% probability of exploitation activity in the next 30 days; percentile 98.

## Sources

- [CVE.org record CVE-2025-54136](https://www.cve.org/CVERecord?id=CVE-2025-54136)
- [NVD entry CVE-2025-54136](https://nvd.nist.gov/vuln/detail/CVE-2025-54136)
- [github.com](https://github.com/cursor/cursor/security/advisories/GHSA-24mc-g4xr-4395)

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Source page: https://erroneo.us/security/cve/CVE-2025-54136/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt