CVE-2025-24912: W1.fi Hostapd Auth Bypass Vulnerability

CVE-2025-24912 Overview

CVE-2025-24912 is a network protocol vulnerability affecting hostapd, an open-source daemon for IEEE 802.11 access point and authentication servers. The vulnerability exists in how hostapd processes RADIUS packets during Wi-Fi device authentication. When hostapd authenticates Wi-Fi devices using RADIUS authentication, an attacker positioned between hostapd and the RADIUS server can inject crafted RADIUS packets, forcing RADIUS authentications to fail.

Critical Impact
An attacker with a man-in-the-middle position can disrupt Wi-Fi authentication by injecting malicious RADIUS packets, causing denial of service for wireless network access.

Affected Products

w1.fi hostapd (all versions prior to patch)

Discovery Timeline

2025-03-12 - CVE-2025-24912 published to NVD
2025-10-24 - Last updated in NVD database

Technical Details for CVE-2025-24912

Vulnerability Analysis

This vulnerability stems from improper processing of crafted RADIUS packets within the hostapd authentication flow. RADIUS (Remote Authentication Dial-In User Service) is a networking protocol that provides centralized authentication, authorization, and accounting management for users who connect to a network service.

When hostapd is configured to authenticate wireless clients against a RADIUS server, it acts as a RADIUS client, forwarding authentication requests and processing responses. The vulnerability allows an attacker positioned in the network path between hostapd and the RADIUS server to inject specially crafted RADIUS packets that the hostapd daemon fails to properly validate or process.

The attack requires network positioning between the hostapd access point and the backend RADIUS server, which increases the complexity of exploitation. However, once positioned, an attacker can systematically disrupt authentication operations, effectively denying wireless network access to legitimate users.

Root Cause

The root cause is related to CWE-826, which involves premature release of a resource during expected lifetime. In this context, hostapd improperly handles certain aspects of RADIUS packet processing, allowing injected packets to interfere with ongoing authentication sessions. The vulnerable code paths fail to adequately validate the authenticity and integrity of RADIUS responses before processing them, enabling the injection attack.

Attack Vector

The attack vector is network-based and requires the attacker to position themselves between the hostapd daemon and the RADIUS authentication server. This man-in-the-middle position could be achieved through various network-level attacks such as ARP spoofing, DNS poisoning, or physical access to network infrastructure. Once positioned, the attacker can observe legitimate RADIUS traffic and inject crafted packets to disrupt the authentication process.

The attack does not require authentication or user interaction, but the high attack complexity (requiring network positioning) reduces the overall risk. Successful exploitation results in availability impact through authentication failure, but does not directly compromise confidentiality or integrity of the system.

Detection Methods for CVE-2025-24912

Indicators of Compromise

Unusual RADIUS authentication failure rates or patterns from the hostapd access point
Unexpected RADIUS packet traffic between hostapd and the RADIUS server
Network anomalies suggesting man-in-the-middle activity on the authentication path
User complaints about intermittent or complete inability to authenticate to wireless networks

Detection Strategies

Monitor RADIUS authentication logs for abnormal failure patterns that deviate from baseline
Implement network intrusion detection to identify suspicious traffic between access points and RADIUS servers
Deploy monitoring for ARP spoofing or other man-in-the-middle techniques on the network segment
Review hostapd daemon logs for unusual error messages related to RADIUS packet processing

Monitoring Recommendations

Enable verbose logging on hostapd to capture detailed RADIUS transaction information
Implement network traffic analysis on the RADIUS communication path
Set up alerting for authentication failure rate thresholds
Monitor for unauthorized devices appearing on network segments between access points and RADIUS servers

How to Mitigate CVE-2025-24912

Immediate Actions Required

Update hostapd to the latest patched version that includes the security fixes
Review network architecture to minimize exposure of RADIUS traffic to potential interception
Consider implementing RADIUS over TLS (RadSec) to protect communications between hostapd and RADIUS servers
Audit network access controls to limit potential man-in-the-middle positions

Patch Information

W1.fi has released patches to address this vulnerability. The fixes are available in the following commits:

Administrators should apply these patches or update to a hostapd version that includes these fixes. Additional details are available in the JVN Security Advisory JVN19358384.

Workarounds

Implement network segmentation to isolate RADIUS traffic from potential attackers
Deploy RADIUS over TLS (RadSec) to encrypt and authenticate RADIUS communications
Use IPsec or other VPN technologies to protect the communication path between hostapd and RADIUS servers
Implement strict network access controls and monitoring on infrastructure segments