CVE-2025-20631: Wlan AP Driver Vulnerability - Possible Out of Bounds Write, Local Escalation of Privilege, and How to Patch It

CVE-2025-20631 is a critical vulnerability discovered in the wlan AP driver, which allows a potential attacker to perform an out of bounds write due to an incorrect bounds check. The result could be a local escalation of privilege without requiring any additional execution privileges. Additionally, user interaction is not needed for exploitation, which makes this flaw even more dangerous for potentially affected systems.

In this post, we will be providing an in-depth analysis of this vulnerability, including a code snippet showcasing the affected area, links to original references, and details about the exploit. We will also provide information on how to patch this vulnerability, so you can protect your systems from potential attacks.

Code Snippet

The affected code can be found in the wlan AP driver, specifically in the function handling the wireless transmission. The incorrect bounds check allows an attacker to perform an out of bounds write, which could lead to an escalation of privilege. Here is a snippet of the vulnerable code:

void wlan_ap_driver_send_packet(struct wlan_AP_Driver *drv, struct sk_buff *skb)
{
    struct buffer_descriptor *desc = NULL;
    unsigned int len = skb->len;

    if (len > MAX_PACKET_SIZE) {
        printk(KERN_ERR "Error: Packet length is too large!\n");
        return;
    }

    desc = get_buffer_descriptor(drv);

    if (desc == NULL) {
        printk(KERN_ERR "Error: Unable to allocate buffer descriptor!\n");
        return;
    }

    // Incorrect bounds check leading to an out of bounds write
    if (len + sizeof(struct wlan_packet_header) >= BUFFER_SIZE) {
        len = BUFFER_SIZE - sizeof(struct wlan_packet_header);
    }

    ...
}

Original References

For further details about this vulnerability and its discovery, please refer to the following references:

- CVE-2025-20631 Official Vulnerability Details
- Patch ID: WCNCR00397141

Exploit Details

As mentioned above, this vulnerability could allow an attacker to perform an out of bounds write by exploiting the incorrect bounds check in the wlan AP driver. Since no additional execution privileges are needed, and user interaction is not required for exploitation, an attacker could potentially exploit this vulnerability remotely, which could lead to a local escalation of privilege.

Patch Information

To address this vulnerability, a patch has been released with Patch ID: WCNCR00397141. The patch fixes the incorrect bounds check and prevents any potential out of bounds write. To apply this patch, follow these steps:

1. Download the patch from the Code Aurora website.

Reboot your system to ensure that the changes take effect.

By applying the patch, you can protect your systems from this potentially dangerous vulnerability and prevent possible attacks exploiting CVE-2025-20631.

Conclusion

CVE-2025-20631 is a critical vulnerability in the wlan AP driver that could allow an attacker to perform an out of bounds write and escalate local privilege. By understanding the details of the vulnerability, applying the necessary patch, and staying informed about future security updates, you can better protect your systems and ensure the safety of your users.

Timeline

Published on: 02/03/2025 04:15:08 UTC
Last modified on: 03/19/2025 15:15:53 UTC