CVE-2023-40164 - Global Buffer Read Overflow Vulnerability in Notepad++ Versions 8.5.6 and Prior

Notepad++ is a popular, free, and open-source source code editor, which is known for its simplicity and efficiency. It is used by developers all around the world to write and edit code in multiple programming languages. Recently, a security vulnerability (CVE-2023-40164) was discovered in Notepad++, affecting versions 8.5.6 and prior. This vulnerability is related to a global buffer read overflow issue in the nsCodingStateMachine::NextStater function.

The following post aims to provide detailed information about this vulnerability, including its exploit details, a code snippet showcasing the issue, and relevant links to original references. It is important to note that as of the time of writing, there are no known patches available for existing versions of Notepad++.

Vulnerability Details

The vulnerability in question is a global buffer read overflow in the nsCodingStateMachine::NextStater function. This issue could potentially be exploited to leak internal memory allocation information, although the full extent of its exploitability remains unclear at this point. Nevertheless, it is a security concern that needs to be addressed for safe and secure usage of Notepad++.

The following code snippet showcases the vulnerable part within the Notepad++ source code

int nsCodingStateMachine::NextState(const unsigned char* aStr, PRUint32 len)
{
    unsigned char c;

    for (int i = ; i < len; ++i)
    {
        c = aStr[i]; // Read from aStr buffer
        mCurrentState = mModel->charToOrderMap[c];
        // Global buffer read overflow
        mCodingSMState = mModel->stateTable[mCurrentState];
    }
}

In the above code snippet, the aStr buffer is being read, and a potential buffer read overflow occurs when assigning a value to mCodingSMState from the stateTable.

The vulnerability, CVE-2023-40164, was initially reported in the following resources

1. Notepad++ GitHub Repository - Issue Tracker
2. National Vulnerability Database (NVD) - CVE-2023-40164

Exploit Details

At this point in time, the exploitability of CVE-2023-40164 remains uncertain. While there is potential for exploiting this global buffer read overflow to leak internal memory allocation information, further research and analysis are required to determine the full scope of possible attacks and damage.

As of the time of publication, no known patches or solutions are available for the existing versions of Notepad++. Users are advised to closely monitor the official Notepad++ website and GitHub repository for updates and security patches.

In conclusion, CVE-2023-40164 is a security vulnerability in Notepad++ versions 8.5.6 and prior, causing a global buffer read overflow in the nsCodingStateMachine::NextStater function. While the full exploitability of this vulnerability is yet to be determined, users should remain vigilant and keep an eye out for any security updates and patches to ensure the safe and secure usage of the Notepad++ source-code editor.

Timeline

Published on: 08/25/2023 21:15:08 UTC
Last modified on: 08/31/2023 17:33:09 UTC