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CVE-2020-3118

Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability

8.8 HighIn KEV

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).

Attack profile

How easy it is to exploit

Attack vector
Adjacent network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

11.7%Up 10.6 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 8.8

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).

Record
CVE-2020-3118
CVSS 3.0
8.8 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-134
Updated
2026-11-02
EUVDEUVD-2020-24389 8.8

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).

Record
EUVD-2020-24389
CVSS 3.0
8.8 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-f7vj-6cqm-9xgc 8.8

A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could...

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).

Record
GHSA-f7vj-6cqm-9xgc
CVSS 3.1
8.8 HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-134, CWE-787
Updated
2026-11-02
CISA KEV No score

Cisco IOS XR Software Discovery Protocol Format String Vulnerability

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.

Record
CVE-2020-3118
Weakness
CWE-134
Updated
2026-11-02
NVD 8.8

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).

Record
CVE-2020-3118
CVSS 3.1
8.8 HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.0
8.8 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
8.3 HighAV:A/AC:L/Au:N/C:C/I:C/A:C
Weakness
CWE-134, CWE-787
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
exploitation
first indexedCVE List, EUVD, GitHub Advisories, CISA KEV, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-3118 is a high vulnerability (CVSS 8.8) in Cisco Ios Xr Software, published February 5, 2020. CISA lists it as known to be exploited, since November 3, 2021. EUVD reports exploitation since November 3, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 11.7%, the 96th percentile. No source names a fixed version.

References

MoveEnter Open