widely-deployed-product-advisoryai-platform-securityendpoint-software-vulnerabilityinitial-access-method

Cursor IDE Flaw Enables Persistent Code Execution via MCP Trust Bypass

Patch & Detection Intelligence · 2 sources · Updated 3mo ago · First seen Aug 12, 2025

Cursor released security updates for a high-severity vulnerability, tracked as CVE-2025-54136 and dubbed MCPoison, that affects versions earlier than 1.3. The flaw stems from how the AI code editor handles configuration changes for MCP (Model Context Protocol) servers, allowing a trust bypass that can lead to remote code execution and, in some cases, full system compromise.

Researchers reported that the issue can be triggered through tampered MCP configuration files on a victim machine or through modified files embedded in GitHub repositories opened by developers, creating a path to persistent code execution inside the development environment. Defenders were urged to upgrade Cursor to version 1.3 immediately and limit the IDE to connections with only trusted MCP servers.

Patch this, or something else?See real exploitation activity before you spend the cycle.

Triage this advisory

Event timeline

How this story unfolded

Events from the most recent confirmed update back to the earliest known activity.

3 events · Aug 5, 2025 – Aug 12, 2025

Aug 12, 20251y ago
CSIRT.SK warns users to upgrade Cursor after vulnerability disclosure
CSIRT.SK issued an advisory about CVE-2025-54136, warning that the vulnerability could be exploited through modified MCP configuration files on a victim device or in GitHub repositories in use. The notice recommended immediately upgrading to Cursor 1.3 and limiting connections to trusted MCP servers.
Vysoko závažná zraniteľnosť v Cursor AI IDE | CSIRT.SK
Aug 12, 20251y ago
Cursor releases fixes for CVE-2025-54136 in version 1.3
The developers of the Cursor AI code editor released security updates in Cursor version 1.3 to fix the high-severity vulnerability CVE-2025-54136, also called MCPoison. The flaw affects versions earlier than 1.3 and can enable remote code execution and full system compromise via MCP trust bypass.
Vysoko závažná zraniteľnosť v Cursor AI IDE | CSIRT.SK
Aug 5, 20251y ago
Check Point publishes MCPoison research on Cursor IDE
Check Point Research published details on CVE-2025-54136, describing MCPoison as a persistent code execution issue in Cursor IDE caused by an MCP trust bypass. The publication publicly documented the vulnerability and its impact on Cursor users.
CVE-2025-54136 – MCPoison Cursor IDE: Persistent Code Execution via MCP Trust Bypass

Linked entities

Related entities

Vulnerabilities, threat actors, malware, products, organizations, and breaches Mallory has linked to this story.

Open in app →

Vulnerabilities

1 linked

MCPoison (CVE-2025-54136)

Affected products

1 linked

Cursor

Organizations

1 linked

Cursor

Do you run this?See real exploitation activity behind this advisory so you can triage it against everything else in the queue.

Prioritize This Patch

Source coverage

Sources

2 references tracked. Mallory keeps watching after this page renders.

Csirt SkNews · Aug 12, 2025

Vysoko závažná zraniteľnosť v Cursor AI IDE | CSIRT.SKOpen source ↗

Check Point Research BlogNews · Aug 5, 2025

CVE-2025-54136 – MCPoison Cursor IDE: Persistent Code Execution via MCP Trust BypassOpen source ↗

Mallory platform

See the full picture, correlated to your attack surface.

This page covers what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which threat actors are using it right now, and what to deploy next.

Start Free Trial Open in App

Exposure mappingMap indicators from this story to your assets and identify affected systems in minutes.

Threat actor evidenceEvery observed campaign, victim, and pivot linked to actors named in this story.

Associated malwareMalware, exploits, and IOCs connected to the activity described here.

Detection signaturesYARA, Sigma, and Snort rules deployed to your SIEM as soon as they’re published.

Scheduled alertsGet matching new stories delivered to your team as they break, not the next morning.

AI threadsAsk questions about this story and take action on the answers.

Cursor IDE Flaw Enables Persistent Code Execution via MCP Trust Bypass

How this story unfolded

CSIRT.SK warns users to upgrade Cursor after vulnerability disclosure

Cursor releases fixes for CVE-2025-54136 in version 1.3

Check Point publishes MCPoison research on Cursor IDE

Related entities

Vulnerabilities

Affected products

Organizations

Sources

See the full picture, correlated to your attack surface.

Related stories

Cursor IDE Executes Malicious `git.exe` From Poisoned Repositories

Cursor IDE DuneSlide Flaws Enable Zero-Click Sandbox Escape and RCE

Anthropic MCP STDIO Design Flaw Enables RCE Across AI Tooling

Cursor IDE Flaw Enables Persistent Code Execution via MCP Trust Bypass

How this story unfolded

CSIRT.SK warns users to upgrade Cursor after vulnerability disclosure

Cursor releases fixes for CVE-2025-54136 in version 1.3

Check Point publishes MCPoison research on Cursor IDE

Related entities

Vulnerabilities

Affected products

Organizations

Sources

See the full picture, correlated to your attack surface.

Related stories

Cursor IDE Executes Malicious `git.exe` From Poisoned Repositories

Cursor IDE DuneSlide Flaws Enable Zero-Click Sandbox Escape and RCE

Anthropic MCP STDIO Design Flaw Enables RCE Across AI Tooling