CVE-2019-25485: R for Windows Buffer Overflow Vulnerability

CVE-2019-25485 Overview

CVE-2019-25485 is a buffer overflow vulnerability in R 3.4.4 on Windows x64 that exists within the GUI Preferences language menu field. This vulnerability allows local attackers to bypass Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) protections. By injecting a crafted payload through the "Language for menus" preference, attackers can trigger a Structured Exception Handler (SEH) chain pivot and execute arbitrary shellcode with application privileges.

Critical Impact

Local attackers can exploit this buffer overflow to bypass Windows security mitigations (DEP/ASLR) and achieve arbitrary code execution within the context of the R application.

Affected Products

• R 3.4.4 on Windows x64

Discovery Timeline

• 2026-03-11 - CVE CVE-2019-25485 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2019-25485

Vulnerability Analysis

This vulnerability is classified under CWE-787 (Out-of-Bounds Write), which occurs when the application writes data past the end or before the beginning of the intended buffer. In R 3.4.4 for Windows x64, the GUI Preferences component fails to properly validate the length of user-supplied input in the language menu field before copying it into a fixed-size buffer.

The attack requires local access to the system where R is installed. An attacker can manipulate the "Language for menus" preference field with an oversized payload designed to overwrite critical memory structures, including the SEH chain. By carefully crafting the payload, the attacker can pivot the exception handler chain to point to attacker-controlled shellcode, effectively bypassing both DEP and ASLR protections implemented by the Windows operating system.

Root Cause

The root cause of this vulnerability is improper bounds checking on user input within the language menu preference handling code. When processing the language preference string, the application copies user-supplied data into a stack buffer without verifying that the input length does not exceed the buffer's allocated size. This allows an attacker to overflow the buffer and corrupt adjacent memory, including SEH records stored on the stack.

Attack Vector

This is a local attack vector vulnerability. An attacker must have local access to the Windows system running R 3.4.4 x64 to exploit this vulnerability. The attack flow involves:

1. Accessing the R GUI Preferences dialog
2. Navigating to the language menu settings
3. Injecting an oversized, specially crafted payload into the language field
4. Triggering an exception that causes the SEH chain to execute attacker-controlled code
5. Achieving arbitrary shellcode execution with the privileges of the R application

The vulnerability allows for SEH-based exploitation techniques that can bypass modern Windows memory protections. For detailed technical information on the exploit mechanism, refer to the Exploit-DB #47122 entry and the VulnCheck Windows Advisory.

Detection Methods for CVE-2019-25485

Indicators of Compromise

• Unexpected crashes or exceptions in the R application (Rgui.exe or R.exe)
• Anomalous memory access patterns or SEH chain modifications detected by endpoint protection
• Presence of suspicious or unusually long strings in R configuration files related to language preferences
• Evidence of shellcode execution within R process memory space

Detection Strategies

• Monitor R application processes for signs of buffer overflow exploitation, including abnormal memory writes and SEH chain manipulations
• Deploy endpoint detection and response (EDR) solutions capable of detecting DEP/ASLR bypass techniques
• Implement application whitelisting to prevent unauthorized code execution from R process context
• Review and audit R configuration files for signs of tampering or malicious payloads

Monitoring Recommendations

• Enable Windows Event Logging for application crashes and exceptions involving R components
• Configure SentinelOne behavioral AI to detect memory corruption attacks targeting statistical software
• Monitor for unusual process spawning or network connections originating from R application processes
• Implement file integrity monitoring on R installation directories and configuration files

How to Mitigate CVE-2019-25485

Immediate Actions Required

• Upgrade R to the latest available version that addresses this buffer overflow vulnerability
• Restrict local access to systems running vulnerable R installations to trusted users only
• Consider running R in a sandboxed or virtualized environment to limit the impact of potential exploitation
• Apply the principle of least privilege to R user accounts and associated processes

Patch Information

Users should update to a newer version of R that addresses this vulnerability. Consult the official R Project website and security advisories for patched versions. For additional technical details on the vulnerability, see the VulnCheck Windows Advisory.

Workarounds

• Disable or restrict access to the GUI Preferences dialog where the vulnerable language menu field is located
• Use the command-line version of R instead of the GUI version on Windows systems where possible
• Implement application-level access controls to prevent untrusted users from modifying R preferences
• Deploy host-based intrusion prevention systems (HIPS) to block exploitation attempts targeting SEH-based attacks