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A technique has been identified that adapts a known port-stealing method to Wi-Fi environments that use multiple BSSIDs. This vulnerability, designated CVE-2026-23809, exploits the relationship between BSSIDs and their associated virtual ports within HPE Aruba Networking Wireless Operating Systems. By leveraging this relationship, an attacker on the same adjacent network can spoof the MAC address of a legitimate client or access point. The attack manipulates the switch’s forwarding table, causing it to associate the victim’s MAC address with the attacker’s physical port. Consequently, traffic destined for the victim is redirected to the attacker, effectively bypassing inter-BSSID isolation controls that are designed to segregate traffic between different virtual networks. Successful exploitation allows the attacker to intercept network traffic, enabling potential eavesdropping on communications, session hijacking by stealing cookies or tokens, or causing a denial of service by disrupting the traffic flow. The CVSS v3.1 vector (AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N) confirms the attack requires adjacent network access, has low complexity, needs no privileges or user interaction, and can lead to limited confidentiality and integrity impacts. The weakness is categorized under CWE-400, Uncontrolled Resource Consumption, as the port-stealing technique can exhaust network resources.
DailyCVE Form:
Platform: HPE Aruba
Version: AOS-10/8
Vulnerability: Inter-BSSID Isolation Bypass
Severity: Medium (5.4)
Date: 04 Mar 2026
Prediction: Patch by 04 May 2026
What Undercode Say:
Analytics:
The vulnerability was discovered by researchers from the University of California and KU Leuven, indicating a high level of academic scrutiny on enterprise wireless implementations. Given the CVSS score of 5.4 and the “Adjacent Network” attack vector, exploitation requires the attacker to be within physical range of the Wi-Fi network. The flaw resides in how HPE Aruba switches handle MAC learning in environments with multiple BSSIDs, making it a design-level issue rather than a simple code bug. While the SSVC analysis indicates “Exploitation: none” at the time of publishing, the public disclosure of the technique increases the likelihood of proof-of-concept code being developed. Enterprises using multi-BSSID setups (e.g., guest networks, IoT VLANs) are most at risk as they rely on isolation to protect sensitive traffic.
Exploit:
The core of the exploit relies on a race condition in the MAC learning process. An attacker would run a script that floods the network with packets claiming the source MAC address is the target victim. Below is a simplified conceptual representation of how an attacker might trigger the vulnerability using tools like `mdk4` or `aireplay-ng` in conjunction with custom scripting.
Attacker machine - Requires a wireless adapter supporting monitor mode. 1. Identify the target client MAC address and the AP's BSSID. Example: Target Client = 00:11:22:33:44:55, AP BSSID = aa:bb:cc:dd:ee:ff 2. Use a tool to send deauthentication packets to the target client to force reconnection. This increases the chance of winning the race condition during the ARP/NDP process. sudo aireplay-ng -0 5 -a aa:bb:cc:dd:ee:ff -c 00:11:22:33:44:55 wlan0mon 3. While the client re-associates, send crafted packets with the client's MAC. This "steals" the port mapping on the switch. The following command (pseudo-code) illustrates the concept: sudo spoof-mac -i wlan0mon -t aa:bb:cc:dd:ee:ff -s 00:11:22:33:44:55 --bssid-hopping 4. After successful port stealing, enable IP forwarding on the attacker machine to intercept and forward the victim's traffic to the real gateway. sudo sysctl net.ipv4.ip_forward=1 5. Use a tool like Wireshark or tcpdump to capture the redirected traffic. sudo tcpdump -i wlan0mon -w captured_traffic.pcap host 00:11:22:33:44:55
Protection from this CVE:
Immediate mitigation involves applying the security patch from HPE once available. In the interim, network administrators should enable features that secure the control plane and validate source MAC addresses. The following commands provide examples of hardening steps on HPE Aruba switches.
Enable dynamic ARP protection to prevent ARP spoofing (if available on the platform). arp-protection validate source-mac Enable IP Source Guard to prevent IP spoofing. ip source-guard Implement port security to limit the number of MAC addresses allowed on a port. interface gigabitethernet 0/0/1 port-security port-security maximum 2 port-security violation protect port-security mac-address sticky Disable MAC learning on specific ports if not required, or tune MAC aging timers. mac-address-table aging-time 300 Ensure that 802.11w (Management Frame Protection) is enabled on the wireless network. This makes deauthentication attacks (used to force reconnects) more difficult. wlan ssid-profile "Corporate_SSID" opmode wpa2-aes management-frame-protection required
Impact:
Successful exploitation compromises the confidentiality and integrity of network communications. An attacker can capture sensitive data such as login credentials, emails, and unencrypted messages (eavesdropping). They can also hijack active web sessions by stealing session cookies (session hijacking). Furthermore, by intercepting and dropping packets, the attacker can effectively sever the victim’s connection to the network (denial of service). The attack bypasses inter-BSSID isolation, meaning traffic from a guest network could potentially be redirected to the corporate network VLAN, breaking critical security boundaries.
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Sources:
Reported By: nvd.nist.gov
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