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Vulnerability Intelligence

CVE-2020-3118

HighExploitedPublic exploit

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.

Published Feb 5, 2020 · Updated Oct 28, 2025

Key Facts

Patch immediately
  • CVE-2020-3118 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting IOS Xr (Cisco), Cisco IOS XR Software.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Oct 20, 2020. Public exploit code is available.
  • EPSS estimates a 12% probability of exploitation in the next 30 days.
  • Fixed versions are available, including IOS Xr 6.6.12, Cisco IOS XR Software 6.6.3.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

8.8

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

12%

Higher than 96.0% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

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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).

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVNov 3, 2021May 3, 2022Not reported
Industry KEV feedOct 20, 2020May 3, 2022Not reported
CIRCL KEVNov 3, 2021May 3, 2022Not reported
ENISA EUVDNov 3, 2021n/aNot reported

Required action: Apply updates per vendor instructions.

Affected Products

7 affected entries in total
ProductAffected versionsFixed in
IOS XrCisco5.2.5, 6.4.2, 6.5.3, 6.6.25, 7.0.16.6.12
Cisco IOS XR Software>= unspecified6.6.3

Patched Releases

IOS Xr

6.6.12

Cisco IOS XR Software

6.6.3

Timeline

  1. Publicly disclosed

    Feb 5, 2020

  2. Added to Industry KEV feed

    Oct 20, 2020

  3. Added to CISA KEV

    Nov 3, 2021

  4. Added to CIRCL KEV

    Nov 3, 2021

  5. Added to ENISA EUVD

    Nov 3, 2021

  6. Last updated

    Oct 28, 2025

Weakness Type

  • CWE-134 Use of Externally-Controlled Format String
  • CWE-787 Out-of-bounds Write

References

2 more references in the full CVE brief

FAQ

Common Questions.

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