high
8.8
CWE
787 20
Advisory Published
Updated

CVE-2021-1368: Cisco FXOS and NX-OS Software Unidirectional Link Detection Denial of Service and Arbitrary Code Execution Vulnerability

First published: Wed Feb 24 2021(Updated: )

A vulnerability in the Unidirectional Link Detection (UDLD) feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code with administrative privileges or cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending crafted Cisco UDLD protocol packets to a directly connected, affected device. A successful exploit could allow the attacker to execute arbitrary code with administrative privileges or cause the Cisco UDLD process to crash and restart multiple times, causing the affected device to reload and resulting in a DoS condition. Note: The UDLD feature is disabled by default, and the conditions to exploit this vulnerability are strict. The attacker needs full control of a directly connected device. That device must be connected over a port channel that has UDLD enabled. To trigger arbitrary code execution, both the UDLD-enabled port channel and specific system conditions must exist. In the absence of either the UDLD-enabled port channel or the system conditions, attempts to exploit this vulnerability will result in a DoS condition. It is possible, but highly unlikely, that an attacker could control the necessary conditions for exploitation. The CVSS score reflects this possibility. However, given the complexity of exploitation, Cisco has assigned a Medium Security Impact Rating (SIR) to this vulnerability.

Credit: ykramarz@cisco.com

Affected SoftwareAffected VersionHow to fix
Cisco NX-OS=8.4\(3.108\)
Cisco NX-OS=8.4\(3.117\)
Cisco MDS 9148S
Cisco MDS 9250i
Cisco MDS 9706 Firmware
Cisco MDS 9710 Firmware
Cisco Nexus 7000
Cisco Nexus 7700 series
Cisco NX-OS=7.0\(3\)i5\(2\)
Cisco NX-OS=7.0\(3\)i7\(9\)
Cisco NX-OS=9.3\(5\)
Cisco Nexus 3048 Firmware
Cisco Nexus 31108PV-V Firmware
Cisco Nexus 31108TC-V Firmware
Cisco Nexus 31128PQ
Cisco Nexus 3132C-Z Firmware
Cisco Nexus 3132Q-V Firmware
Cisco Nexus 3132Q-X/3132Q-XL
Cisco Nexus 3132Q-XL Firmware
Cisco Nexus 3164Q Firmware
Cisco Nexus 3172PQ/PQ-XL
Cisco Nexus 3172PQ-XL Firmware
Cisco Nexus 3232C
Cisco Nexus 3264C-E Firmware
Cisco Nexus 3264Q Firmware
Cisco Nexus 3408-S Firmware
Cisco Nexus 34180YC Firmware
Cisco Nexus 3432D-S Firmware
Cisco Nexus 3464C Firmware
Cisco Nexus 3524-xl
Cisco Nexus 3524-XL Firmware
Cisco Nexus 3548-X/XL
Cisco Nexus 3548-X/XL
Cisco Nexus 36180YC-R Firmware
Cisco Nexus 3636C-R Firmware
Cisco NX-OS Nexus 9000 Series
Cisco Nexus 92160YC Switch
Cisco Nexus 9221C Firmware
Cisco Nexus 92300YC Firmware
Cisco Nexus 92304QC Switch
Cisco Nexus 92348GC-X Switch
Cisco Nexus 9236C Switch
Cisco Nexus 9272Q Switch
Cisco Nexus
Cisco Nexus 93108TC-EX-24 Firmware
Cisco Nexus 93108TC-FX Switch
Cisco Nexus 93108TC-FX Switch
Cisco Nexus 93120TX Firmware
Cisco Nexus 93128 Firmware
Cisco Nexus 9316D-GX Firmware
Cisco Nexus 93180LC-EX Switch
Cisco Nexus 93180YC-EX-24
Cisco Nexus 93180YC-EX-24 Firmware
Cisco Nexus 93180YC-FX Firmware
Cisco Nexus 93180YC-FX-24 Firmware
Cisco Nexus 93180YC-FX3 Firmware
Cisco Nexus 93180YC-FX3S Firmware
Cisco Nexus 93216TC-FX2 Firmware
Cisco Nexus 93240YC-FX2 Firmware
Cisco Nexus 9332PQ Firmware
Cisco Nexus 93360YC-FX2
Cisco Nexus 9336C-FX2 Firmware
Cisco Nexus 9336C-FX2-E Firmware
Cisco Nexus N9336PQ
Cisco Nexus 9348GC-FXP Firmware
Cisco Nexus 93600CD-GX Firmware
Cisco Nexus 9364c-h1
Cisco Nexus 9364C-GX Firmware
Cisco Nexus 9372PX-E
Cisco Nexus 9372PX-E Firmware
Cisco Nexus 9372TX
Cisco Nexus 9372TX-E Switch
Cisco Nexus 9396PX Firmware
Cisco Nexus 9396TX Firmware
Cisco Nexus 9508
Cisco NX-OS=7.3\(8\)n1\(1\)
Cisco NX-OS=7.3\(9\)n1\(0.823\)
Cisco Nexus 5548P Firmware
Cisco Nexus 5548UP Firmware
Cisco Nexus 5596T Firmware
Cisco Nexus 5596UP Firmware
Cisco 56128p
Cisco Nexus 5624Q Firmware
Cisco Nexus 5648Q Firmware
Cisco Nexus 5672UP-16G
Cisco Nexus 5672UP-16G Firmware
Cisco Nexus 5696Q Firmware
Cisco Nexus 6001 Firmware
Cisco Nexus 6004 Firmware
Cisco Unified Computing System software<4.0\(4i\)
Cisco Unified Computing System software>=4.1<4.1\(2c\)
Cisco UCS 6248UP
Cisco UCS 6296UP
Cisco UCS 6324 firmware
Cisco UCS 6332
Cisco UCS 6332-16UP
Cisco UCS 64108
Cisco UCS 6454 Fabric Interconnect
Cisco Firepower Extensible Operating System=r231
Cisco Firepower 4110 Next-Generation Firewall
Cisco Firepower 4112 Firmware
Cisco Firepower 4115
Cisco Firepower 4120 Next-Generation Firewall
Cisco Firepower 4125 firmware
Cisco Firepower 4140 Next-Generation Firewall
Cisco Firepower 4145 firmware
Cisco Firepower 4150 Next-Generation Firewall
Cisco Firepower 9300 firmware

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-1368?

    CVE-2021-1368 has a critical severity rating due to its potential to allow unauthenticated adjacent attackers to execute arbitrary code.

  • How do I fix CVE-2021-1368?

    To mitigate CVE-2021-1368, update the affected devices to the latest version of Cisco FXOS or NX-OS software as recommended by Cisco.

  • What devices are affected by CVE-2021-1368?

    CVE-2021-1368 affects certain versions of Cisco FXOS and NX-OS Software, specifically versions 7.0(3)i5(2), 8.4(3.108), and 9.3(5), among others.

  • What type of vulnerability is CVE-2021-1368?

    CVE-2021-1368 is a remote code execution vulnerability that can also lead to denial of service conditions.

  • Can CVE-2021-1368 be exploited remotely?

    CVE-2021-1368 requires an adjacent attacker, meaning that the attacker must be on the same local network for exploitation.

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