# CVE-2020-3118: Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability

> CVE-2020-3118: Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability. CVSS 8.8 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2020-3118
Last updated: 2025-10-21T23:35:52Z

- Published: 2020-02-05 17:40 UTC · Updated: 2025-10-21 23:35 UTC · Assigner: cisco
- CVSS: 8.8 (CVSS 3.1) · Severity: High · Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS: 11.7%, 96th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2021-11-03, federal due date 2022-05-03, ransomware use: Unknown
- CWE: CWE-134

## Description

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).

## CISA required action

Apply updates per vendor instructions.

## Affected vendors and products

- Cisco: Cisco IOS XR Software

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2020-3118)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2020-3118)
- [http://packetstormsecurity.com/files/156203/Cisco-Discovery-Protocol-CDP-Remote-Device-Takeover.html](http://packetstormsecurity.com/files/156203/Cisco-Discovery-Protocol-CDP-Remote-Device-Takeover.html)
- [https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200205-iosxr-cdp-rce](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200205-iosxr-cdp-rce)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2020-3118 · Markdown: https://rewindex.com/cve/CVE-2020-3118.md · JSON: https://rewindex.com/api/v1/cves/CVE-2020-3118 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:06:35.779Z