CVE-2025-27558: IEEE 802.11 Mesh Networks RCE Vulnerability

CVE-2025-27558 Overview

CVE-2025-27558 is a critical protocol vulnerability affecting IEEE P802.11-REVme D1.1 through D7.0, enabling FragAttacks (fragmentation and aggregation attacks) against Wi-Fi mesh networks. This vulnerability allows adversaries to inject arbitrary frames into mesh networks utilizing Wi-Fi Protected Access (WPA, WPA2, or WPA3) or Wired Equivalent Privacy (WEP) security protocols. The attack specifically targets devices that support receiving non-SSP A-MSDU frames, bypassing the security mechanisms intended to protect wireless communications.

This vulnerability exists as a result of an incomplete fix for CVE-2020-24588, which originally addressed similar frame injection issues in the 802.11 standard. The P802.11-REVme specification, as of early 2025, represents a planned release of the 802.11 standard that inadvertently reintroduced this attack surface.

Critical Impact

Attackers can exploit this vulnerability to inject malicious frames into secured mesh networks, potentially compromising the confidentiality and integrity of wireless communications without requiring authentication.

Affected Products

• IEEE P802.11-REVme D1.1 through D7.0 compliant devices
• Mesh network devices supporting non-SSP A-MSDU frame reception
• Wi-Fi devices using WPA, WPA2, WPA3, or WEP in mesh configurations

Discovery Timeline

• 2025-05-21 - CVE-2025-27558 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-27558

Vulnerability Analysis

The vulnerability stems from improper verification of data authenticity (CWE-345) in the IEEE 802.11 wireless protocol specification. FragAttacks exploit fundamental design flaws in how the 802.11 protocol handles frame fragmentation and aggregation, particularly affecting Aggregated MAC Service Data Unit (A-MSDU) processing.

In mesh network deployments, devices must process fragmented frames to reassemble complete data units. The vulnerability allows an attacker within wireless range to craft malicious A-MSDU frames that appear legitimate to the receiving device. These frames can be injected into protected network traffic, effectively bypassing the encryption and authentication mechanisms provided by WPA, WPA2, WPA3, or WEP.

The attack leverages the fact that certain devices accept non-SSP (Simplified Security Protocol) A-MSDU frames without proper validation. This creates an opportunity for frame injection that was supposed to be addressed by the original CVE-2020-24588 fix, but the remediation proved incomplete for mesh network scenarios.

Root Cause

The root cause is insufficient verification of data authenticity in the A-MSDU frame processing implementation within the IEEE P802.11-REVme specification. The protocol fails to adequately validate the source and integrity of aggregated frames in mesh network topologies, allowing adversaries to inject arbitrary frames that are processed as legitimate traffic.

The incomplete fix for CVE-2020-24588 left mesh networks particularly vulnerable because the remediation did not account for all edge cases in mesh network frame forwarding and aggregation scenarios.

Attack Vector

The attack is network-based and can be executed remotely within wireless range of the target mesh network. An adversary does not require authentication or prior access to exploit this vulnerability. The attack sequence involves:

1. Positioning within range of the target mesh network
2. Monitoring wireless traffic to identify vulnerable devices accepting non-SSP A-MSDU frames
3. Crafting malicious A-MSDU frames with injected payloads
4. Transmitting the crafted frames to vulnerable mesh network devices
5. The receiving device processes the injected frames as legitimate traffic

The vulnerability allows injection of arbitrary data into the secured wireless communication stream, potentially enabling traffic interception, data manipulation, or further network penetration. For detailed technical analysis of FragAttacks and exploitation methodology, refer to the GitHub FragAttack Survey Repository.

Detection Methods for CVE-2025-27558

Indicators of Compromise

• Unexpected or malformed A-MSDU frames appearing in wireless traffic captures
• Anomalous frame injection patterns detected by wireless intrusion detection systems
• Devices receiving frames with unexpected source addresses within mesh networks
• Increased frame fragmentation activity without corresponding legitimate traffic

Detection Strategies

• Deploy wireless intrusion detection systems (WIDS) configured to monitor for FragAttack signatures
• Implement network monitoring for anomalous A-MSDU frame patterns and unexpected fragmentation behavior
• Enable detailed logging on wireless access points and mesh network nodes to capture frame-level events
• Utilize packet capture tools to analyze 802.11 frame headers for signs of injection attacks

Monitoring Recommendations

• Continuously monitor mesh network traffic for unauthorized frame injection attempts
• Configure alerts for devices receiving non-SSP A-MSDU frames from unexpected sources
• Review wireless network logs regularly for patterns consistent with FragAttacks exploitation
• Implement baseline traffic analysis to detect deviations indicative of active exploitation

How to Mitigate CVE-2025-27558

Immediate Actions Required

• Identify all mesh network devices potentially affected by this vulnerability
• Disable non-SSP A-MSDU frame reception where supported by device firmware
• Implement network segmentation to isolate critical mesh network infrastructure
• Monitor affected networks for signs of active exploitation while awaiting vendor patches

Patch Information

Organizations should monitor vendor announcements for firmware and driver updates that address this vulnerability. The Debian LTS Security Announcement provides guidance for Debian-based systems. Contact your wireless equipment vendors for specific patch availability and deployment timelines.

As this vulnerability relates to the IEEE P802.11-REVme specification itself, comprehensive remediation may require both protocol-level fixes in future standard revisions and implementation-level patches from individual device manufacturers.

Workarounds

• Configure mesh network devices to reject non-SSP A-MSDU frames where configuration options exist
• Implement additional network layer encryption (such as VPN tunnels) for sensitive mesh network traffic
• Reduce wireless transmission power to limit the physical attack surface
• Deploy additional network monitoring to detect exploitation attempts while awaiting patches