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CVE-2021-1523— Cisco Nexus 9000 Series Fabric Switches ACI Mode Queue Wedge Denial of Service Vulnerability

Quick assessment

Affected
Cisco Cisco NX-OS System Software in ACI Mode
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Cisco Nexus 9000 Series Fabric Switches是美国思科（Cisco）公司的一款9000系列光纤交换机。 Cisco Nexus 9000 Series Fabric Switches 中存在输入验证错误漏洞，该漏洞源于产品对特定端口的TCP流量处理不当。攻击者可通过向交换机的 Switched Virtual Interface 端口发送特质数据包引发漏洞。

CVSS 8.6 · High EPSS 1.33% · P70

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2021-1523

Vulnerability Information
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Vulnerability Title
Cisco Nexus 9000 Series Fabric Switches ACI Mode Queue Wedge Denial of Service Vulnerability
Source: CVE Program / CVE List V5
Vulnerability Description
A vulnerability in Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, remote attacker to cause a queue wedge on a leaf switch, which could result in critical control plane traffic to the device being dropped. This could result in one or more leaf switches being removed from the fabric. This vulnerability is due to mishandling of ingress TCP traffic to a specific port. An attacker could exploit this vulnerability by sending a stream of TCP packets to a specific port on a Switched Virtual Interface (SVI) configured on the device. A successful exploit could allow the attacker to cause a specific packet queue to queue network buffers but never process them, leading to an eventual queue wedge. This could cause control plane traffic to be dropped, resulting in a denial of service (DoS) condition where the leaf switches are unavailable. Note: This vulnerability requires a manual intervention to power-cycle the device to recover.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
对已超过有效生命周期的资源丧失索引
Source: CVE Program / CVE List V5
Vulnerability Title
Cisco Nexus 9000 Series Fabric Switches 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Cisco Nexus 9000 Series Fabric Switches是美国思科（Cisco）公司的一款9000系列光纤交换机。 Cisco Nexus 9000 Series Fabric Switches 中存在输入验证错误漏洞，该漏洞源于产品对特定端口的TCP流量处理不当。攻击者可通过向交换机的 Switched Virtual Interface 端口发送特质数据包引发漏洞。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Cisco Cisco NX-OS System Software in ACI Mode n/a -

II. Public POCs for CVE-2021-1523

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III. Intelligence Information for CVE-2021-1523

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Vendor Advisories for CVE-2021-1523 (1)

Same Patch Batch · Cisco · 2021-08-25 · 15 CVEs total

CVE-2021-1577 9.1 CRITICAL Cisco Application Policy Infrastructure Controller Arbitrary File Read and Write Vulnerabi
CVE-2021-1578 8.8 HIGH Cisco Application Policy Infrastructure Controller Privilege Escalation Vulnerability
CVE-2021-1588 8.6 HIGH Cisco NX-OS Software MPLS OAM Denial of Service Vulnerability
CVE-2021-1587 8.6 HIGH Cisco NX-OS Software VXLAN OAM (NGOAM) Denial of Service Vulnerability
CVE-2021-1586 8.6 HIGH Cisco Nexus 9000 Series Fabric Switches ACI Mode Multi-Pod and Multi-Site TCP Denial of Se
CVE-2021-1579 8.1 HIGH Cisco Application Policy Infrastructure Controller App Privilege Escalation Vulnerability
CVE-2021-1581 6.5 MEDIUM Cisco Application Policy Infrastructure Controller Command Injection and File Upload Vulne
CVE-2021-1580 6.5 MEDIUM Cisco Application Policy Infrastructure Controller Command Injection and File Upload Vulne
CVE-2021-1584 6.0 MEDIUM Cisco Nexus 9000 Series Fabric Switches ACI Mode Privilege Escalation Vulnerability
CVE-2021-1591 5.8 MEDIUM Cisco Nexus 9500 Series Switches Access Control List Bypass Vulnerability
CVE-2021-1582 5.4 MEDIUM Cisco Application Policy Infrastructure Controller Stored Cross-Site Scripting Vulnerabili
CVE-2021-1590 5.3 MEDIUM Cisco NX-OS Software system login block-for Denial of Service Vulnerability
CVE-2021-1583 4.4 MEDIUM Cisco Nexus 9000 Series Fabric Switches ACI Mode Arbitrary File Read Vulnerability
CVE-2021-1592 4.3 MEDIUM Cisco UCS Manager Software SSH Sessions Denial of Service Vulnerability

IV. Related Vulnerabilities

Same product: Cisco NX-OS System Software in ACI Mode
Same vendor: Cisco
Same weakness: CWE-772

V. Comments for CVE-2021-1523

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