Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability

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).

Weakness: CWE-134, CWE-787

Patcharo shows this vulnerability for information but does not match versions for this product yet.

• Cisco Cisco IOS XR Software · unspecified < 6.6.3

• 20200205 Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability(opens in a new tab)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-3118(opens in a new tab)

Cisco (CVE record)

Cisco (CVE record) · 27 Sept 2026, 23:46 UTC · Parser patcharo-cve5/1.1.0

CISA Known Exploited Vulnerabilities

CISA Known Exploited Vulnerabilities · 27 Sept 2026, 23:42 UTC · Parser patcharo-kev/1.0.0

NVD

NVD · 27 Sept 2026, 23:44 UTC · Parser patcharo-nvd/1.0.0

FIRST EPSS

FIRST EPSS · 27 Sept 2026, 23:46 UTC · Parser patcharo-epss/1.0.0

Last verified: 28 Sept 2026, 02:31 UTC