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CVE-2021-34714— Multiple Cisco Operating Systems Unidirectional Link Detection Denial of Service Vulnerability

Quick assessment

Affected
Cisco Cisco IOS
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 NX-OS Software等都是美国思科（Cisco）公司的产品。Cisco NX-OS Software是一套交换机使用的数据中心级操作系统软件。Cisco IOS是一套为其网络设备开发的操作系统。IOS XE是一套为其网络设备开发的操作系统。 Cisco FXOS 软件、Cisco IOS 软件、Cisco IOS XE 软件、Cisco IOS XR 软件和 Cisco NX-OS 软件存在输入验证错误漏洞，该漏洞源于软件的单向链路检测(UDLD)功能对UDLD报文的输入验证不正确。漏

CVSS 7.4 · High EPSS 0.39% · P30

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2021-34714

Vulnerability Information
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Vulnerability Title
Multiple Cisco Operating Systems Unidirectional Link Detection Denial of Service Vulnerability
Source: CVE Program / CVE List V5
Vulnerability Description
A vulnerability in the Unidirectional Link Detection (UDLD) feature of Cisco FXOS Software, Cisco IOS Software, Cisco IOS XE Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload. This vulnerability is due to improper input validation of the UDLD packets. An attacker could exploit this vulnerability by sending specifically crafted UDLD packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The UDLD feature is disabled by default, and the conditions to exploit this vulnerability are strict. An attacker must have full control of a directly connected device. On Cisco IOS XR devices, the impact is limited to the reload of the UDLD process.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
输入验证不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
多款Cisco产品输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Cisco NX-OS Software等都是美国思科（Cisco）公司的产品。Cisco NX-OS Software是一套交换机使用的数据中心级操作系统软件。Cisco IOS是一套为其网络设备开发的操作系统。IOS XE是一套为其网络设备开发的操作系统。 Cisco FXOS 软件、Cisco IOS 软件、Cisco IOS XE 软件、Cisco IOS XR 软件和 Cisco NX-OS 软件存在输入验证错误漏洞，该漏洞源于软件的单向链路检测(UDLD)功能对UDLD报文的输入验证不正确。漏
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 IOS n/a -

II. Public POCs for CVE-2021-34714

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III. Intelligence Information for CVE-2021-34714

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Vendor Advisories for CVE-2021-34714 (1)

Same Patch Batch · Cisco · 2021-09-23 · 33 CVEs total

CVE-2021-34770 10.0 CRITICAL Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Exe
CVE-2021-1619 9.8 CRITICAL Cisco IOS XE Software NETCONF and RESTCONF Authentication Bypass Vulnerability
CVE-2021-34727 9.8 CRITICAL Cisco IOS XE SD-WAN Software Buffer Overflow Vulnerability
CVE-2021-1624 8.6 HIGH Cisco IOS XE Software Rate Limiting Network Address Translation Denial of Service Vulnerab
CVE-2021-1622 8.6 HIGH Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers Common Open Policy Servi
CVE-2021-1615 8.6 HIGH Cisco Embedded Wireless Controller Software for Catalyst Access Points Denial of Service V
CVE-2021-1611 8.6 HIGH Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers EoGRE Denial of Servic
CVE-2021-1565 8.6 HIGH Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Denial of Servi
CVE-2021-34769 8.6 HIGH Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Denial of Servi
CVE-2021-34768 8.6 HIGH Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Denial of Servi
CVE-2021-1419 7.8 HIGH Cisco Access Points SSH Management Privilege Escalation Vulnerability
CVE-2021-1623 7.7 HIGH Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers Simple Network Managemen
CVE-2021-1620 7.7 HIGH Cisco IOS and IOS XE Software IKEv2 AutoReconnect Feature Denial of Service Vulnerability
CVE-2021-34699 7.7 HIGH Cisco IOS and IOS XE Software TrustSec CLI Parser Denial of Service Vulnerability
CVE-2021-1621 7.4 HIGH Cisco IOS XE Software Interface Queue Wedge Denial of Service Vulnerability
CVE-2021-34767 7.4 HIGH Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers IPv6 Denial of Service
CVE-2021-34740 7.4 HIGH Cisco Aironet Access Points WLAN Control Protocol Packet Buffer Leak Denial of Service Vul
CVE-2021-34703 6.8 MEDIUM Cisco IOS and IOS XE Software Link Layer Discovery Protocol Denial of Service Vulnerabilit
CVE-2021-34729 6.7 MEDIUM Cisco IOS XE SD-WAN Software Command Injection Vulnerability
CVE-2021-34725 6.7 MEDIUM Cisco IOS XE SD-WAN Software Command Injection Vulnerability

Showing top 20 of 33 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Cisco IOS
Same vendor: Cisco
Same weakness: CWE-20

V. Comments for CVE-2021-34714

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