Overview

A critical vulnerability, CVE-2025-5865, has been discovered in the RT-Thread 5.1.0, a widely-used open-source real-time operating system. The vulnerability resides in the sys_select function of the file rt-thread/components/lwp/lwp_syscall.c, specifically within the component Parameter Handler. The incorrect handling of the timeout argument leads to a memory corruption issue, which, if exploited, could lead to potential system compromise or data leakage. Due to the severity of the vulnerability, it is crucial for users and administrators to understand the risk and take immediate action to mitigate the threat.

Vulnerability Summary

CVE ID: CVE-2025-5865
Severity: Critical (CVSS Score: 8.0)
Attack Vector: Local
Privileges Required: Low
User Interaction: None
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

RT-Thread | 5.1.0

How the Exploit Works

The vulnerability originates from the mishandling of the timeout argument in the sys_select function. An attacker can manipulate this argument leading to a memory corruption issue. The vendor explained that the timeout parameter should be checked for access rights in kernel mode and should only be temporarily used in kernel memory. If not done correctly, the corrupted memory could be manipulated to execute arbitrary code or expose sensitive data, leading to potential system compromise or data leakage.

Conceptual Example Code

The following is a conceptual example of how the vulnerability might be exploited. This is a pseudocode representation and not an actual code:

#include "rt-thread/components/lwp/lwp_syscall.h"
void exploit() {
int timeout = INT_MAX; // Manipulate the timeout value
// Call the vulnerable function with manipulated timeout value
int result = sys_select(..., timeout);
if (result != 0) {
// The memory is now corrupted, carry out the exploit
execute_arbitrary_code();
}
}

In the above pseudocode, the timeout variable is manipulated to a value that could lead to memory corruption when passed to the sys_select function. If the function call is successful (i.e., returns non-zero), the attacker can then proceed to exploit the corrupted memory.

Mitigation

The vendor has provided a patch to correct this vulnerability. All users and administrators are urged to apply this patch as soon as possible. As a temporary mitigation, users can also use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) to detect and prevent potential exploitation attempts.