Persistent code execution via stale MCP approval
Published Aug 1, 2025 · Updated Aug 4, 2025
Trust bypass in Anysphere Cursor 1.2.4 and earlier allows remote authenticated users to execute arbitrary code via modified MCP files. Cursor binds approval to an mcpServers entry name without checking whether its command or arguments change, so altered definitions execute silently. Exploitation requires prior approval of the entry and later repository write access or arbitrary local file-write access, yielding persistent execution in the user's context.
Summary
What happened
Trust bypass in Anysphere Cursor 1.2.4 and earlier allows remote authenticated users to execute arbitrary code via modified MCP files. Cursor binds approval to an mcpServers entry name without checking whether its command or arguments change, so altered definitions execute silently. Exploitation requires prior approval of the entry and later repository write access or arbitrary local file-write access, yielding persistent execution in the user's context.
The record
- CVE
- CVE-2025-54136
- Published
- Aug 1, 2025
- Updated
- Aug 4, 2025
- Vendor
- Anysphere
- Product
- Cursor
- Classifications
- CWE-78, CWE-494, T1059, T1204.002
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 1, 2025CVE publishedPublication date reported by the CVE source.
- Aug 4, 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.
- Affected versionversion=< 1.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- MCPoison proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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