MongoDB Compass EUVD-2026-31127

The attack requires the victim to actively import a specially crafted CSV file using the CSV import feature within MongoDB Compass (CVSS UI:P - passive interaction, meaning a standard workflow action suffices rather than clicking a warning or unusual prompt). The attacker controls only the file path delivered to shell.openExternal(), not any command-line arguments, which limits the execution surface to whatever the OS default handler for that path type will do. The malicious path must reference a resource accessible on the victim's local filesystem or via a registered OS protocol handler for execution to occur. No attacker-side authentication is required (PR:N), but the attack depends entirely on social engineering or supply-chain compromise to deliver the malicious CSV to a user who will import it. The vulnerability does not affect MongoDB server instances or any network-exposed surface - it is isolated to the local Compass desktop application and triggered exclusively through the CSV import workflow.

The CVSS 4.0 score of 5.3 (Medium) reflects several partially mitigating factors: UI:P (passive user interaction - the victim must perform a standard import action), and impact limited to VI:L (low integrity on the vulnerable system) with no confidentiality or availability impact and no subsequent-system scope. AV:N, AC:L, AT:N, and PR:N confirm the malicious CSV can be delivered remotely with no attacker-side privileges and no special timing or race conditions required. No EPSS score was provided in the available data, preventing quantitative exploitation-probability comparison. The CVE is not listed in CISA KEV and no proof-of-concept has been identified, indicating no confirmed in-the-wild exploitation at time of analysis. The EUVD tags 'Information Disclosure' alongside 'Prototype Pollution,' which partially conflicts with the description's primary focus on command execution via shell.openExternal(); this may reflect tagging of the path-leakage component of the pollution chain, but the description makes clear the primary concern is command execution. Real-world risk is moderate: the attack is not zero-interaction, but CSV imports are a core, routine Compass workflow, lowering the social engineering bar in operational environments.

An attacker crafts a CSV file with prototype-polluting column headers (e.g., a key of __proto__ mapping to a local script path or a custom OS protocol URI) and delivers it to a Compass user via a plausible channel such as a data export from a compromised system, an email attachment, or a shared analytics file. The victim, performing a routine import in MongoDB Compass, loads the file through the standard CSV import workflow. During parsing, the polluted prototype causes the attacker-supplied file path to reach Electron's shell.openExternal(), instructing the OS to open the path with its default handler - potentially executing a local binary or script. No public proof-of-concept has been identified at time of analysis.