CVE-2025-27558 is a critical vulnerability identified in the draft versions D1.1 through D7.0 of the IEEE P802.11-REVme standard, which governs Wi-Fi mesh networking protocols. The vulnerability allows an unauthenticated remote attacker to exploit FragAttacks—fragmentation and aggregation attacks—against mesh networks that use Wi-Fi Protected Access (WPA, WPA2, WPA3) or the deprecated Wired Equivalent Privacy (WEP) protocols. Specifically, the issue arises because devices supporting reception of non-SSP (Security Service Provider) Aggregated MAC Service Data Unit (A-MSDU) frames can be tricked into accepting maliciously crafted frames injected by an attacker. This flaw is a regression caused by an incorrect fix for a previous vulnerability, CVE-2020-24588, indicating that the underlying protocol handling remains flawed. The attacker can inject arbitrary frames without requiring any privileges or user interaction, enabling potential data interception, manipulation, or injection within the mesh network. The vulnerability impacts the confidentiality and integrity of communications but does not directly affect availability. The CVSS v3.1 score of 9.1 reflects the ease of exploitation over a network, lack of required privileges, and the high impact on confidentiality and integrity. As P802.11-REVme is a forthcoming standard, affected devices are likely those implementing early drafts or pre-release firmware. No patches or exploits are currently publicly available, but the severity necessitates proactive mitigation.

For European organizations, this vulnerability poses a significant threat to the security of mesh Wi-Fi networks, which are increasingly deployed in enterprise, industrial, and public infrastructure settings. Successful exploitation could allow attackers to intercept sensitive communications, inject malicious data, or manipulate network traffic, undermining confidentiality and integrity. This is particularly critical for sectors relying on secure wireless communications such as finance, healthcare, government, and critical infrastructure. The lack of required authentication and user interaction lowers the barrier for attackers, increasing risk. Given the vulnerability affects WPA3 as well, even networks using the latest security protocols are not immune. The potential for lateral movement within mesh networks could facilitate broader compromise of connected devices. European organizations with mesh deployments in smart cities, manufacturing, or transport systems face heightened risk. The absence of known exploits currently provides a window for mitigation but also indicates the need for vigilance as exploit development is likely imminent.

Organizations should immediately inventory and identify any devices implementing IEEE P802.11-REVme drafts or pre-release firmware supporting mesh networking. Coordinate with vendors and manufacturers to obtain firmware updates or patches addressing this vulnerability once available. Until patches are released, restrict mesh network exposure by segmenting mesh traffic from sensitive systems and limiting wireless access to trusted devices only. Disable support for non-SSP A-MSDU frame reception if configurable, to reduce attack surface. Employ network monitoring tools capable of detecting anomalous frame injection or fragmentation attacks within mesh networks. Implement strong network access controls and consider fallback to more mature Wi-Fi standards where feasible. Regularly update device firmware and maintain an inventory of wireless infrastructure to ensure timely patching. Engage with industry groups and standards bodies to track updates on P802.11-REVme and related security advisories. Finally, conduct penetration testing focused on mesh network security to identify potential exploitation paths.