CVE-2026-33989

HighPublic PoC

Published: 27 March 2026

Published

27 March 2026

Modified

31 March 2026

KEV Added

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Patch

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CVSS Score 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

EPSS Score 0.0001 3.4th percentile

Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-33989 is a high-severity Path Traversal (CWE-22) vulnerability in Mobilenexthq Mobile Mcp. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 3.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

This vulnerability is AI-related — categorised as AI Agent Protocols and Integrations; in the Protocol-Specific Risks risk domain.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly requires validation of saveTo and output parameters to block path traversal sequences before filesystem operations.

SI-2 Flaw Remediation good match

prevent

Mandates identification, reporting, and correction of the path traversal flaw, such as upgrading to version 0.0.49.

AC-3 Access Enforcement partial match

prevent

Enforces logical access controls to restrict file writes outside the intended workspace even if traversal occurs.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1565.001 Stored Data Manipulation Impact

Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data.

attack.mitre.org →

Why these techniques?

Path traversal in network-accessible MCP server enables initial exploitation via T1190; resulting arbitrary overwrites of critical files directly facilitate stored data manipulation (T1565.001) for integrity/availability impact.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

Mobile Next is an MCP server for mobile development and automation. Prior to version 0.0.49, the `@mobilenext/mobile-mcp` server contains a Path Traversal vulnerability in the `mobile_save_screenshot` and `mobile_start_screen_recording` tools. The `saveTo` and `output` parameters were passed directly to filesystem operations…

without validation, allowing an attacker to write files outside the intended workspace. Version 0.0.49 fixes the issue.

Deeper analysisAI

CVE-2026-33989 is a path traversal vulnerability (CWE-22, CWE-73) affecting the `@mobilenext/mobile-mcp` server, part of Mobile Next, an MCP server used for mobile development and automation. In versions prior to 0.0.49, the `mobile_save_screenshot` and `mobile_start_screen_recording` tools insecurely handle the `saveTo` and `output` parameters, passing them directly to filesystem operations without validation. This allows arbitrary file writes outside the intended workspace. The vulnerability has a CVSS v3.1 base score of 8.1 (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H) and was published on 2026-03-27.

An unauthenticated attacker with network access to the server can exploit this vulnerability by tricking a user into invoking the affected tools with specially crafted `saveTo` or `output` parameters, such as those using directory traversal sequences like `../`. Successful exploitation enables writing files to arbitrary locations on the server's filesystem, potentially overwriting critical files and resulting in high integrity and availability impacts, though no confidentiality loss.

The GitHub security advisory (GHSA-3p2m-h2v6-g9mx), release notes for version 0.0.49, and fixing commit (f5e32295903128c1e71cf915ae6c0b76c7b0153b) confirm that upgrading to version 0.0.49 resolves the issue by adding proper validation to the parameters before filesystem operations. Security practitioners should prioritize updating affected instances and review logs for suspicious tool invocations.