CVE-2026-20173: Allocation of Resources Without Limits or Throttling in Cisco Cisco NX-OS Software
Description
A vulnerability in Cisco NX-OS Software could allow an unauthenticated, remote attacker to exhaust system resources, causing a denial of service (DoS) condition. This vulnerability exists because rate limiting was improperly applied to some protocols. An attacker could exploit this vulnerability by sending a high rate of UDP or TCP connections to a data plane interface on an affected device. A successful exploit could allow the attacker to cause instability to various routing and control plane protocols through some packet loss and temporary disruptions, causing a DoS condition. This DoS condition will clear without manual intervention soon after the high rate of traffic is stopped.
CVSS v3.1
Score 5.8medium
Affected software
Cisco
Cisco NX-OS Software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in Cisco NX-OS Software arises from improper application of rate limiting to certain protocols. An unauthenticated remote attacker can exploit this by flooding a data plane interface with a high volume of UDP or TCP connections. This resource exhaustion leads to instability in routing and control plane protocols due to packet loss and temporary disruptions, causing a denial of service. The condition is transient and clears once the attack traffic ceases.
Potential Impact
An attacker can cause a denial of service by exhausting system resources on affected Cisco NX-OS devices, leading to temporary instability and packet loss in routing and control plane protocols. This disruption affects availability but does not impact confidentiality or integrity. The DoS condition resolves automatically after the attack stops.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing network-level rate limiting or filtering to reduce the impact of high-rate UDP or TCP connection floods targeting data plane interfaces.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 2025-10-08T11:59:15.392Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ac674862cdf04f65664731c
Added to database: 10/07/2026, 16:34:14 UTC
Last enriched: 10/07/2026, 17:04:43 UTC
Last updated: 10/08/2026, 05:48:07 UTC
Views: 10
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