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Findings

CVE-2020-3118

Cisco IOS XR Software Discovery Protocol Format String Vulnerability

Published Feb 5, 2020 · updated Jun 16, 2026 · cisco ios xr

A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certain fields in Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to cause a stack overflow, which could allow the attacker to execute arbitrary code with administrative privileges on an affected device. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

Timeline

Detection, updates, and resolution for this record.

  1. Feb 5, 2020 · Catalog

    Detected

    A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certain fields in Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisc

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. May 3, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certain fields in Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisc

Required action

Apply updates per vendor instructions.

CISA due date May 3, 2022

Affected

  • cpe cisco/ios xrversion unspecified
  • cpe cisco/ios xr5.2.5
  • cpe cisco/ios xr6.4.2
  • cpe cisco/ios xr6.5.3
  • cpe cisco/ios xr6.6.25
  • cpe cisco/ios xr7.0.1
  • vendor Cisco IOS XRversion unspecified

Sources

  • CISA KEVCVE-2020-3118

    Cisco IOS XR improperly validates string input from certain fields in Cisco Discovery Protocol messages. Exploitation could allow an unauthenticated, adjacent attacker to execute code with administrative privileges or cause a reload on an affected device.

    cisa.gov
  • CVE.orgCVE-2020-3118

    Official CVE identifier

    cve.org
  • FIRST EPSSCVE-2020-3118

    30-day exploitation probability 11.7%

    first.org
  • NIST NVDCVE-2020-3118

    A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certa

    nvd.nist.gov
  • Packet Storm Securityhttp://packetstormsecurity.com/files/156203/Cisco-Discovery-Protocol-CDP-Remote-Device-Takeover.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References