No exploitation reportedFix available

CVE-2018-0303

Q: Is CVE-2018-0303 actively exploited?

Active exploitation of CVE-2018-0303 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2018-0303?

CVE-2018-0303 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2018-06-21
WeaknessCWE-119 · CWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability in the Cisco Discovery Protocol component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code as root or cause a denial of service (DoS) condition on the affected device. The vulnerability exists because of insufficiently validated Cisco Discovery Protocol packet headers. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to a Layer 2 adjacent affected device. A successful exploit could allow the attacker to cause a buffer overflow that could allow the attacker to execute arbitrary code as root or cause a DoS condition on the affected device. This vulnerability affects the following if configured to use Cisco Discovery Protocol: Firepower 4100 Series Next-Generation Firewalls, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc22202, CSCvc22205, CSCvc22208, CSCvc88078, CSCvc88150, CSCvc88159, CSCvc88162, CSCvc88167.

Timeline

dates in UTC

2018-06-2111:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-0303?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-0303?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Cisco nx-osversion to verify

Branch	Affected	Fixed in	Source
7.0	= 7.0\(0\)hsk\(0.357\)	no fix published	NVD
8.1	= 8.1\(0.2\)s0	no fix published	NVD
8.8	= 8.8\(0.1\)	no fix published	NVD
8.0	= 8.0\(1\)	no fix published	NVD
8.8	= 8.8\(3.5\)s0	no fix published	NVD
7.0	= 7.0\(3\)i4\(7\)	no fix published	NVD
7.0	= 7.0\(3\)i7\(1\)	no fix published	NVD
3.1	= 3.1\(3a\)a	no fix published	NVD

Cisco firepower extensible operating systemversion to verify

Branch	Affected	Fixed in	Source
2.2	≥ 2.2.2, < 2.2.2.17	2.2.2.17	NVD
2.2	≥ 2.2.1, < 2.2.1.70	2.2.1.70	NVD
2.1	≥ 2.1.1, < 2.1.1.86	2.1.1.86	NVD
2.0	≥ 2.0, < 2.0.1.153	2.0.1.153	NVD
1.1	≥ 1.1, < 1.1.4.179	1.1.4.179	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

tools.cisco.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-11-29
OpenCVESSVC decisionnone—
NVDCVSS 3.08.8read 2026-10-23
NVDCVSS 2.08.3read 2026-10-23
CNAweakness (CWE)CWE-20read 2026-10-23
NVDweakness (CWE)CWE-119read 2026-10-23
FIRST EPSSEPSS score1.1 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2018-06-21
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2018-0303?

Is CVE-2018-0303 actively exploited?

Active exploitation of CVE-2018-0303 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-0303?

CVE-2018-0303 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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