CVE-2025-41713: Network Switch Auth Bypass Vulnerability

CVE-2025-41713 Overview

CVE-2025-41713 describes a boot-time race condition in a network switch that permits an unauthenticated remote attacker to send traffic to unauthorized networks. During a short window while the device initializes, the switch operates in an undefined state. Proper VLAN and port isolation only takes effect after a CPU-induced reset applies the intended configuration. The issue is tracked under CWE-1188: Insecure Default Initialization of Resource and documented in CERT@VDE Advisory VDE-2025-083. Attack complexity is low and no authentication or user interaction is required.

Critical Impact
Attackers on an adjacent or routable network can bridge into segments that should be isolated during the switch boot window, undermining network segmentation controls.

Affected Products

Network switch product referenced in CERT@VDE advisory VDE-2025-083
See the CERT@VDE CSAF document for the authoritative affected product list and firmware versions
Deployments relying on the affected switch for VLAN or network segmentation enforcement

Discovery Timeline

2025-09-15 - CVE-2025-41713 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-41713

Vulnerability Analysis

The vulnerability is a boot-time initialization flaw in the switch's data plane. When the device powers on, the switching fabric becomes active before the CPU has loaded and applied the intended forwarding configuration. During this interval, the switch forwards frames according to an undefined default state rather than the operator-configured VLAN, ACL, or port isolation policy.

Because the data plane is reachable from the network during this window, an unauthenticated remote attacker who can send frames to the device may traverse boundaries that would normally be blocked. Traffic can reach networks that should be logically separated. A subsequent CPU-driven reset of the switching subsystem installs the proper configuration and closes the gap.

The classification under [CWE-1188] reflects the root problem: a resource — the switching fabric — is enabled with insecure defaults before secure initialization completes. Impact is limited to confidentiality and availability at low severity, with no direct integrity impact recorded in the assigned metrics.

Root Cause

The switching hardware initializes into a permissive forwarding state prior to configuration load. Segmentation policies enforced by the control plane are not applied atomically with data-plane activation, producing a race between packet forwarding and configuration application.

Attack Vector

Exploitation requires network access and the ability to transmit frames toward the switch during its boot sequence. An attacker who can trigger or wait for a device reboot — for example, during scheduled maintenance, power events, or induced outages — may inject traffic that reaches otherwise unreachable segments. No credentials or user interaction are required. Verified proof-of-concept code is not publicly available.

No verified exploit code is available for this vulnerability. Refer to the CERT@VDE advisory VDE-2025-083 for authoritative technical detail.

Detection Methods for CVE-2025-41713

Indicators of Compromise

Unexpected traffic flows between VLANs or network segments observed immediately after a switch reboot
ARP or MAC address table entries appearing in segments where the source host should not be reachable
SPAN or netflow records showing east-west communication that violates documented segmentation policy during device startup windows

Detection Strategies

Correlate switch reboot and link-up events with flow telemetry to identify traffic that crosses segmentation boundaries within seconds of boot
Deploy passive network monitoring on trunk and inter-segment links to baseline expected traffic and alert on policy-violating flows
Review switch syslog and SNMP trap streams for boot events followed by unexpected MAC learning across VLANs

Monitoring Recommendations

Ingest switch syslog, NetFlow/IPFIX, and configuration change events into a centralized analytics platform for cross-source correlation
Alert on any device reboot on infrastructure that enforces segmentation between trust zones
Track dwell time between power-on and configuration-applied states to quantify exposure per reboot

How to Mitigate CVE-2025-41713

Immediate Actions Required

Inventory affected switches using the CPE and product identifiers listed in CERT@VDE VDE-2025-083
Restrict physical and logical access to switch management and uplink ports to prevent opportunistic traffic injection during reboots
Schedule reboots during controlled maintenance windows and monitor traffic for the duration of the boot cycle

Patch Information

Consult the vendor advisory referenced by CERT@VDE at VDE-2025-083 and the associated CSAF document for fixed firmware versions and upgrade procedures. Apply the vendor-supplied firmware update on all affected devices.

Workarounds

Enforce segmentation upstream using a device not affected by the boot-time flaw, such as a router or firewall configured with strict ACLs
Use link-state or port-based controls on connected devices so upstream ports remain administratively down until the switch signals a fully configured state
Where feasible, disconnect untrusted uplinks before rebooting the switch and reconnect only after configuration application is verified

bash

# Example: upstream ACL to constrain traffic while a downstream switch reboots
# Apply on the router or firewall aggregating the affected switch
access-list 150 permit ip 10.10.10.0 0.0.0.255 10.10.10.0 0.0.0.255
access-list 150 deny   ip 10.10.10.0 0.0.0.255 any
access-list 150 deny   ip any 10.10.10.0 0.0.0.255
interface GigabitEthernet0/1
 ip access-group 150 in
 ip access-group 150 out