A vulnerability in the errdisable per VLAN feature of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause the device to crash, leading to a denial of service (DoS) condition. The vulnerability is due to a race condition that occurs when the VLAN and port enter an errdisabled state, resulting in an incorrect state in the software. An attacker could exploit this vulnerability by sending frames that trigger the errdisable condition. A successful exploit could allow the attacker to cause the affected device to crash, leading to a DoS condition.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ios_xe | Cisco | 3.6(5) (including) | 3.6(5) (including) |
A race condition occurs within concurrent environments, and it is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc. A race condition violates these properties, which are closely related:
A race condition exists when an “interfering code sequence” can still access the shared resource, violating exclusivity. The interfering code sequence could be “trusted” or “untrusted.” A trusted interfering code sequence occurs within the product; it cannot be modified by the attacker, and it can only be invoked indirectly. An untrusted interfering code sequence can be authored directly by the attacker, and typically it is external to the vulnerable product.